However, its emissions to the atmosphere have gone largely unchecked because the microbial and environmental controls governing N2O emissions have proven difficult to manage. The microbial process N2O consumption is the only know biotic pathway to remove N2O from soil pores and therefore reduce N2O emissions. Consequently, manipulating soils to increase N2O consumption by organic carbon (OC) additions has steadily gained interest. However, the response of N2O emissions to different OC additions are inconsistent, and it is unclear if lower N2O emissions are due to increased consumption, decreased production, or both. Simplified and systematic studies are needed to evaluate the efficacy of different OC additions on N2O consumption. We aimed to manipulate N2O consumption by amending soils with OC compounds  more directly available to denitrifiers. We hypothesized that N2O consumption is OC‐limited and predicted these denitrifier‐targeted additions would lead to enhanced N2O consumption and increased nosZ gene abundance. We incubated diverse soils in the laboratory and performed a 15N2O isotope pool dilution assay to disentangle microbial N2O emissions from consumption using laser‐based spectroscopy. We found that amending soils with OC increased gross N2O consumption in six of eight soils tested. Furthermore, three of eight soils showed Increased N2O Consumption and Decreased N2O Emissions (ICDE), a phenomenon we introduce in this study as an N2O management ideal. All three ICDE soils had low soil OC content, suggesting ICDE is a response to relaxed C‐limitation wherein C additions promote soil anoxia, consequently stimulating the reduction of N2O via denitrification. We suggest, generally, OC additions to low OC soils will reduce N2O emissions via ICDE. Future studies should prioritize methodical assessment of different, specific, OC‐additions to determine which additions show ICDE in different soils.Nitrous oxide (N 2O) is a potent greenhouse gas. The microbial process N2O consumption is the only know biotic pathway to remove N2O from soil pores and therefore reduce N2O emissions. We aimed to stimulate N2O consumption by amending eight different soils with organic carbon (OC) compounds more directly available to denitrifiers. OC amendments increased N2O consumption in 6/8 soils, and 3/8 soils showed Increased N2O Consumption and Decreased N2O Emissions (ICDE). All ICDE soils had low OC, suggesting ICDE is a response to relaxed C‐limitation. We suggest, generally, OC additions to low OC soils will reduce N2O emissions via ICDE.Nitrous oxide (N Thus, the N2O and label 15N2O concentrations measured in the headspace of the incubation system were ultimately driven by biological processes of N2O production and consumption in the soil. Red arrows indicate fluxes that affect the bulk N2O pool while blue arrows indicate fluxes that affect the label 15N2O. In this study, we quantify gross N2O consumption by tracking the disappearance of label 15N2O over time. We also quantify net emission as the change in bulk N2O concentration over time.To disentangle the kinetics of N2O consumption and thereby reduce net N2O emissions. To enhance N2O consumption, we added OC to soils and compared the N2O consumption rates and net N2O emission rates in control versus manipulated soils. In response to OC amendment, we looked for Increased gross N2O Consumption and Decreased net N2O Emissions (ICDE) in soils. From a GHG management perspective, it would be ideal to induce ICDE in any soil. Here we explored how amending soils with organic carbon (OC) provides an electron donor source for enhanced N2O → N2 reduction, which corresponds to N2O consumption. When some soils showed an ICDE response, but others did not, we examined the factors that explained the response.In our experiment, we sought to stimulate N2O consumption is how altering organic matter supply might affect the N2O sources and sinks. Organic matter additions have been the focus of many N2O management studies  laser‐based N2O isotopic analyzer. This methodology is distinct from previous studies that used gas flow‐through of intact soil cores  that can limit exchange of the 15N2O label between the headspace and the loci of consumption. Second, added organic matter can be more homogeneously distributed through sieved soils than intact soils. Third, we depend on a 48‐h incubation time to maximize diffusive exchange of the 15N2O label between soil microbes and the incubation container headspace. In addition, the laser‐based N2O isotopic analyzer is effective at near‐ambient N2O concentrations , has much faster throughput (~15 min per sample), and minimal sample preparation . However, these methods use gas chromatography (GC) or conventional isotope ratio mass spectrometry (IRMS). IRMS typically requires significantly elevated N2O concentrations and/or pre‐concentration  in the 15N gas flux method can yield 15N2O through a wide variety of processes including bacterial denitrification, fungal denitrification, dissimilatory nitrate reduction to ammonium (DNRA), or abiotic processes, etc. , we hypothesized that N2O consumption is generally OC limited. In this experiment, we aimed to manipulate N2O consumption by amending soils with the abovementioned electron donors that are more exclusively available to denitrifiers, rather than to fermenters. We predicted that these targeted additions would stimulate nosZ abundance and lead to enhanced N2O consumption  to investigate how underlying properties of the different soils would impact their capacity to consume N2O. All soils were held at 60% water saturation, amended with non‐fermentable organic acids , and incubated in the laboratory for 48 hr. We used the above‐described novel 15N2O isotope pool dilution technique to disentangle microbial N2O emissions from consumption , so within those designated areas 10 soil cores were collected randomly. The sites Sky Pond, Loch Vale, and Fenske Lake Cabins represented broader geographic areas , so 10 soil cores were collected at randomly assigned GPS points within ~150 m of the GPS coordinates for the site  and nitrate (NO3−) were extracted from soils in a 5:1 2 M KCl to soil mixture. Mixtures were mechanically swirled on a shaker table with a 25 mm orbital diameter at 250 rpm for 60 min, settled for 60 minutes, and then gravity filtered. Extracts were analyzed colorimetrically with an Alpkem FIA wet chemistry system . We determined GWC by drying 10 g soil subsamples to a constant weight at 105°C.Prior to freezing soils, we measured soil inorganic N (IN) via KCl extractions and calculated soil gravimetric water content (GWC). We also measured soil IN concentrations after all soils had been incubated. Ammonium , and soil organic nitrogen (SON). We measured soil pH from slurries of 10:1 deionized (DI) water to soil with a benchtop meter (Thermo Scientific Orion Star™ A211 Benchtop pH Meter). Frozen soil subsamples were dried in a 60°C oven, ground to powder on a table roller, and then combusted for SOC and SON analysis with a LECO Tru‐Spec CN analyzer (Leco Corp.).2.3For all incubations, we held soils at 60% soil saturation. To determine how much water to add to each soil to achieve this saturation, we determined the maximum water holding capacity for each soil. First, we amended thawed subsamples of frozen, field‐moist soil with DI water until fully saturated. Then, we dried these subsamples to a constant weight at 105°C and calculated saturated water content by dividing the g water in the subsample by the subsample dry soil mass. We used this metric rather than % water‐filled pore space because in sieving our soils we broke down all soil pore structures. Finally, to determine the g of water to add to a given soil, we used Equation  to a final concentration of 6.28 mg/L. All organic compounds were obtained from Sigma Aldrich. Aqueous solutions were stored at 4°C when not in use.The organic acids used are all non‐fermentable, naturally occurring, and have previously been determined by Hedin et al.  to impac2.4.2Soils were separated into either Control, or OC‐amended (+OC) groups. For all incubations, the frozen soil equivalent of 75 g dry soil was weighed into 0.5 L Ball jars and refrigerated overnight to thaw. Prior to treatment, all soils were removed from the refrigerator and warmed to room temperature over ~1 h. To bring all soils to 60% saturation, Control soils were amended with DI water and +OC soils were amended with DI water and 1 ml of the +OC solution. Either amendment was distributed by pipette over the soils. After all liquid was added to a given soil, it was thoroughly mixed to ensure sufficient distribution of OC (if applied) and homogenous saturation.2O] and isotopic analysis with our laser‐based analyzer  but without CO2 and water vapor, as these gases contribute to optical peak broadening effects  and time 48 (T48) measurements to enable a 48 h assay duration. Soils were incubated on a lab countertop at room temperature (24°C) for either 60 min  or 49 h (T48). At the end of the incubation period, we mixed each jar and gas bag's air by attaching a 60 ml syringe to the jar's gas sampling port and, by opening the stopcock valve connecting the jar headspace to the gas bag, then we pumped the syringe for ~ 60 seconds to homogenize the jar headspace and Tedlar gas bag (Stuchiner and von Fischer We performed time zero (2.4.3T0) or 49 h (T48), incubation vessels were analyzed for N2O concentration and isotopic composition by a laser‐based LGR N2O isotopic analyzer . Gas was sampled from each incubation vessel for 12–15 min (or until the N2O concentration stabilized) at a flow rate of 42 ml/min into the analyzer. We removed CO2, water vapor and volatile organics from the sample air using a Nafion–carbosorb–silica gel scrubbing system. Removing these gases minimizes the optical peak‐broadening effects inherent to laser‐based analyzers , where they were trimmed to only include stabilized N2O isotopocule readings . These values were used to calculate average N2O and isotopomer concentrations. All reported concentrations were then corrected against calibrations using the model and approach described in Stuchiner et al. . Sample air was admitted to the analyzer by injecting 3 ml of air samples into a continuous flow of zero‐grade air  that was connected to the analyzer via an open split. All baseline GHG concentrations were <10 ppm, and each injected sample yielded a CO2 concentration peak. The height  of these peaks were calibrated against a four‐point calibration curve generated with CO2 standards from Airgas  that were also injected into the analyzer when zero‐grade air was flowing through it.We measured accumulated CO2.4.42O emissions using measures of the headspace N2O concentration and calculated gross N2O consumption using isotope pool dilution  is the amount of labeled N2O at time t. Substituting *N2O48 and t = 48, the solution for k is: Gross Nnd Hedin , which cEquation  and modiEquation , (3)ln2O, the amount of labeled N2O in the incubation jar headspace, as the product of the total headspace N2O concentration and the AP excess (APE) 15Nbulk in the N2O.We calculated *N2O and its isotopomers were calibrated using equations from Stuchiner et al.  fraction of emitted N2O. Then we calculated the AP of the heavy isotope (AP) for each sample using Equation  in 2019 (www.N2Olevels.org). Each gross consumption rate was expressed in units ng N2O‐N/g dry soil/day.These excess Equation  to calcu2.4.515N15N16O into the headspace of each jar using a 3 ml syringe. After mixing the jar and gas bag air thoroughly, this raised the N2O concentration and the δ15Nbulk on average to ~500 ppb and ~6300‰, respectively. Six vessels were sampled for N2O and isotopomer concentrations at T0 and the remaining six vessels were sampled at T48. All samples were measured on our LGR N2O isotopic analyzer. t‐Tests revealed that changes from T0 to T48 in total N2O concentration were not significant, while changes in concentration of enriched 15N2O was less than 2.3% for δ15Nα and δ15Nβ.A separate test assessed the gastight seals of the incubation vessels. Twelve incubation vessels were flushed and filled with zero‐grade air and injected with 1 ml of 99 AP 2.4.6T48 incubations, soil replicates from each group were bulked into a Ziploc bag and re‐homogenized. Soil IN was measured immediately thereafter, as in Section After all gas had been sampled for the 2−) to nitric oxide (NO) and is, thus, characteristic of incomplete denitrification, and the nosZ gene encodes the enzyme that catalyzes reduction of N2O to N2 and is thus characteristic of complete denitrification , we extracted DNA from soils that had been frozen at −80°C using a Qiagen Powersoil Pro kit according to the manufacturer's instructions (Qiagen). The nifH gene encodes the enzyme that catalyzes N‐fixation, the nirK gene encodes the enzyme that catalyzes reduction of nitrite —“Taking Off Again” © 2020 The R Foundation for Statistical Computing). All data used for statistical analyses are openly available at Mountain Scholar: Digital Collection of Colorado and Wyoming  to examine the associations among variables and ICDE. We used the package 33.12O consumption in six of the eight incubated soils . To better discern which properties were important drivers of ICDE, we performed subsequent one‐way ANOVAs to assess differences among soils for each property individually. As illustrated in Figure p < .0001, Figure p = .095 for Δ nosZ:nirK and p = .148 for Δ nifH, Figure We performed a MANOVA regressing all the soil and microbial properties we measured versus the ICDE categories (hereafter categorized as “Yes ICDE” or “No ICDE”). The MANOVA revealed that at least one of the properties impacted whether a soil showed ICDE or not (4+ (p < .0001) and NO3− (p < .0001) concentrations , the Colorado cornfield having the second highest soil NO3− concentration , and the urban lawn having the third highest soil NO3− concentration  1 explained more than 50% of the variation among the variables, whereas PC2 explained approximately 17% of the variation among the variables . Plots associated with t‐tests can be found in the Supplementary Information . However, the joint response of consumption and N2O emission differed among soils. Three soils showed ICDE while three other soils increased N2O consumption but also increased N2O emissions  and electron acceptors, such as O2 consumption, creating a greater soil volume where N2O reduction could occur  would both drive Oobertson  found thn et al.  saw C ad4.12O consumption rates increased in response to +OC treatment in most, but not all, the soils tested , or they had depressed N2O consumption following OC amendment . The soils that did not show ICDE were characterized by high SOM, and in response to OC amendment, had variable changes in soil NO3− and in soil microbial respiration, and little change in the ratio of nosZ:nirK genes , it is possible that the OC additions helped to create suboxic/anoxic microsites by stimulating microbial respiration . The increased NO3− production in the Minnesota cornfield also aligns with the idea of coupled nitrification‐denitrification, which has been associated with anoxic microsites in oxic soils  reductant limited. As a result, those soils might have been less responsive to the OC amendment  limited. This raises the question, where does the OC‐limitation threshold lie for different soils, and how can we predict it? What other variables mediate this threshold? Being able to identify the amount of OC a soil requires to induce ICDE, and if in fact that soil is a good candidate for +OC treatment  could be useful for screening soils as targets for N4.44 emissions, or if CO2 emissions from microbial respiration offset N2O consumption (Li et al., 2O reduction to offset any CO2 or CH4 emissions from +OC treatment. Additionally, as the N2O management community continues to explore organic amendments to decrease net N2O emissions, it will be important to better understand which specific additions are most effective at reducing net emissions. Studies have illustrated that certain OC amendments can increase net N2O emissions (Guenet et al., 2O consumption could be central for GHG management, particularly in agroecosystems. These systems are projected to become an increasingly important source of GHGs as the human population grows, so developing strategies to curtail their emissions while sustainably feeding people will be instrumental for the future (Bakken & Frostegård, It remains unresolved how the +OC treatment impacts other soil microbial community responses. Specifically, we did not examine how amending soils with OC affected CHThe authors declare no conflict of interest.Supplementary MaterialClick here for additional data file.


Here, we have investigated the effect of A2A and A2B‐selective agonists on vasodilatation in three distinct vascular beds of the rat cardiovascular system. NanoBRET ligand binding studies were used to confirm receptor selectivity. The regional hemodynamic effects of adenosine A2A and A2B selective agonists were investigated in conscious rats. Male Sprague‐Dawley rats (350–450 g) were chronically implanted with pulsed Doppler flow probes on the renal artery, mesenteric artery, and the descending abdominal aorta. Cardiovascular responses were measured following intravenous infusion (3 min for each dose) of the A2A‐selective agonist CGS 21680  or the A2B‐selective agonist BAY 60‐6583  following predosing with the A2A‐selective antagonist SCH 58261 (0.1 or 1 mg kg−1 min−1), the A2B/A2A antagonist PSB 1115 (10 mg kg−1 min−1) or vehicle. The A2A‐selective agonist CGS 21680 produced a striking increase in heart rate (HR) and hindquarters vascular conductance (VC) that was accompanied by a significant decrease in mean arterial pressure (MAP) in conscious rats. In marked contrast, the A2B‐selective agonist BAY 60‐6583 significantly increased HR and VC in the renal and mesenteric vascular beds, but not in the hindquarters. Taken together, these data indicate that A2A and A2B receptors are regionally selective in their regulation of vascular tone. These results suggest that the development of A2B receptor agonists to induce vasodilatation in the kidney may provide a good therapeutic approach for the treatment of acute kidney injury.Adenosine is a local mediator that regulates changes in the cardiovascular system via activation of four G protein‐coupled receptors (A We have previously shown that adenosine can elicit vasodilatation in the renal, mesenteric, and hindquarters’ vascular beds of conscious rats that is not attenuated by the selective A1‐receptor antagonist DPCPX and is likely to be mediated by A2 receptors.2 receptor contributes to vasodilatation in different vascular beds has not been investigated previously. In the present study, we have used selective agonists for the A2A (CGS 21680)2B (BAY 60‐6583)2A and A2B receptor stimulation in conscious, freely‐moving rats and compared the effect of each agonist on vascular flow in three different vascular beds  simultaneously.Although A22.1N‐ethyl‐β‐D‐ribofuranuronamidosyl)‐9H‐purin‐2‐yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680 hydrochloride) (Cat#1063), 2‐(2‐Furanyl)‐7‐(2‐phenylethyl)‐7H‐pyrazolotriazolopyrimidin‐5‐amine (SCH 58261) (Cat#2270), 2‐‐2‐pyridinyl]thio]‐acetamide (BAY 60‐6583) (Cat#4472), 4‐‐benzenesulfonic acid (PSB 1115) (Cat#2009), 8‐[4‐[4‐(4‐Chlorophenzyl)piperazide‐1‐sulfonyl)phenyl]]‐1‐propylxanthine (PSB 603) (Cat#3198), 1‐(6‐Amino‐9H‐purin‐9‐yl)‐1‐deoxy‐N‐ethyl‐β‐D‐ribofuranuronamide (NECA) (Cat#1691), and (±)‐‐N‐[2‐Hydroxy‐5‐[1‐hydroxy‐2‐[[2‐(4‐methoxyphenyl)‐1‐methylethyl]amino]ethyl]phenyl] formamide hemifumarate (formoterol) (Cat#1448) were purchased from Tocris Bioscience . Dimethyl Sulfoxide (DMSO) (Cat#D5879) and Bovine Serum Albumin (BSA) (Cat#A7030) were purchased from Sigma‐Aldrich . The fluorescent ligand, CA200645, was purchased from Hello Bio,  (Cat#HB7812). Exclusively for the in vitro experiments described, the ligands were dissolved in DMSO from powdered stocks to 10−2 M prior to the commencement of the experiment.4‐. Statistical comparisons between groups of animals were performed on the integrated changes over specified time periods. A Friedman‘s test, which is a nonparametric, repeated‐measures analysis of variance, was used for within‐group comparisons, and a Wilcoxon rank‐sum test for integrated area under or above curve analysis was used for comparisons between groups. A Wilcoxon test was also performed for comparisons between groups at a specific time point. VCs were calculated from the MAP and Doppler shift (flow) data. A value of p < .05 was considered significant.All in vivo data were collected and analyzed using IdeeQ software . For all experiments, time‐averaged data are shown as changes from baseline  is the agonist concentration and EC50 is the molar concentration of agonist required to generate 50% of the EMAX. For all statistical analyses, a value of p < .05 was considered significant.For GloSensor experiments, concentration‐response curves were fitted to the following equation:33.1For each individual study, baseline measurements taken before the administration of the adenosine receptor agonists SCH 58261 or PSB 1115, adenosine receptor agonists and their corresponding vehicle controls are shown in Table 3.22A antagonist), PSB 1115 (A2B antagonist), or respective vehicle control was administered. The effects of the A2A and A2B antagonists were evaluated for 10 min  group were determined by evaluating difference between groups  and between groups at given time points;  alone caused sustained and significant increases in MAP, accompanied by vascular constrictions in the renal and mesenteric vascular beds  were given via intravenous infusion , and also inhibited the increase in HR and fall in MAP  on the cardiovascular responses to CGS 21680   produced dose‐dependent significant increases in HR and VC in the renal and mesenteric vascular beds  and highest (40 μg kg−1 min−1) doses of BAY 60‐6583  only had a small effect on the increase in HR and no significant effect on the increase in VC observed in the renal vascular bed  bioluminescence resonance energy transfer (BRET) have provided advantages over the traditional ligand binding assays.2A and A2B receptors.2A and A2B receptors in conjunction with the fluorescent xanthine amine congener‐based antagonist CA200645.2AR and A2BR  .2A and A2B receptors respectively.2B‐selective antagonist PSB 603, the response to the A2A agonist CGS 21680 (mediated via A2A receptors) was significantly attenuated by simultaneous treatment with BAY 60‐6583 , however, had no significant effect on the response to formoterol  of conscious freely moving rats. Previous work in ex vivo models  has confirmed that both A2A and A2B receptors can produce vasodilatation in different vascular beds, including the kidney and coronary circulations.2A knock‐out mice are also known to be hypertensive.1‐receptor antagonist DPCPX and is likely to be mediated by A2 receptors.2A‐ (CGS 21680)2B‐ (BAY 60‐6583)2A and A2B receptor stimulation on VC.In the present study, we set out to evaluate the effect of selective activation of A2A and A2B receptors, we employed a NanoBRET ligand binding study using N‐terminal nanoluciferase‐tagged receptors and the fluorescent ligand CA200645. CA200645 is a fluorescent analog based on the nonselective adenosine receptor antagonist xanthine amine congener.2A (PKD 7.02) and A2B (PKD 7.43) receptors . It therefore seems likely that any antagonism of the hindquarters’ VC response to CGS 21680 is due to an effect of PSB 1115 on A2A receptors. Unfortunately, solubility issues prevented us from using the more A2B selective antagonist PSB 603 for in vivo experiments.CGS 21680 had a good affinity for the rat Nluc‐tagged A2B‐receptor , confirming that these effects were mediated by A2B‐receptors.BAY 60‐6583 had a good affinity for the rat Nluc‐tagged A2A and A2B receptors are regionally selective in their regulation of vascular tone. Thus, A2A‐receptors mediate a large vasodilatation in the hindquarters with smaller, more limited effects on VC in the renal and mesenteric vascular beds. In contrast, A2B receptor stimulation leads to a large increase in VC in both the renal and mesenteric circulations with no effect on the hindquarters. Interestingly, selective activation of vasodilator responses to A2A or A2B receptor activation both caused a strong increase in HR, but only the A2A effect in the hindquarters is accompanied by a fall in MAP. The tachycardia in the heart following A2A receptor activation is most likely due to a baroreflex excitation of the sympathetic nervous system,2B receptors in the posterior hypothalamus of the rat.Taken together, these data indicate that A2B receptors with BAY 60‐6583 is the marked increase observed in VC in the renal and mesenteric circulation, with only a minor effect on the VC in the hindquarters and MAP. Adenosine has been previously observed to cause vasodilatation in the renal circulation,2B receptor.2A receptor, which can elicit afferent arteriolar vasodilation by activating KATP channels.2A agonist CGS 21680 in the renal or mesenteric circulations in our studies. These data suggest that the A2B receptor is primarily responsible for an increase in VC in the renal vasculature.A striking feature of the selective activation of A2A and A2B receptor stimulation and, as mentioned earlier, these are likely to be a result of baroreflex excitation of the sympathetic nervous system in the posterior hypothalamus.2A‐mediated vasodilatation in the hindquarters that is matched with both an increase in HR and a fall in MAP. More surprising was that large increases in VC in the renal and mesenteric circulations induced by A2B receptor activation were not accompanied by a change in MAP. In the kidney, A2B and A2A receptors are located in the renal vasculature and cause renovascular dilatation and increased renin secretion.2B receptor activation.A major advantage of the Doppler flowmetry model is that it can monitor multiple cardiovascular changes in a conscious rat, where compensatory reflex mechanisms are still operational. This explains why marked increases in HR are observed with both A2B receptor has been demonstrated to play an important role in renal ischemic reperfusion injury by improving post‐ischemic renal peritubular capillary flow.2B receptor activation is abolished in A2B receptor knock‐out mice, and BAY 60‐6583 treatment can dramatically improve renal function in wild‐type mice.2B receptor knock‐out mice and with BAY 60‐6583 for mesenteric ischemia.2B‐receptor activation produces a vasodilatation in the rat that is selective to particular vascular beds  and is not accompanied by changes in blood pressure. This result suggests that the development of A2B receptor agonists to induce vasodilatation in the kidney and mesentery may provide a good therapeutic approach for the treatment of acute kidney injury and mesenteric ischemia.The A2A‐receptor activation plays a major role in suppressing immune responses,2A‐receptor antagonists are in clinical trials for the treatment of cancer because of their ability to prevent adenosine‐mediated suppression of immune responses in cancer.2B‐receptors in acute kidney injury and mesenteric ischemia has potential to avoid some of the immunosuppressive actions of A2A‐receptor agonists. However, it remains possible that A2B‐receptor activation may also contribute to the suppression of the immune system by adenosine, and dual A2A/A2B receptor antagonists are currently undergoing clinical trials in cancer.AThe authors declare no conflicts of interest.Participated in the research design: Samantha L. Cooper, Edward S. Wragg, Jeanette Woolard, and Stephen J. Hill. Performed the molecular biology: Mark Soave and Edward S. Wragg. Conducted the experiments: Samantha L. Cooper, Edward S. Wragg, and Patrizia Pannucci. Performed the data analysis: Samantha L. Cooper, Edward S. Wragg, Stephen J. Hill, and Jeanette Woolard. Wrote or contributed to the writing of the manuscript: Samantha L. Cooper, Edward S. Wragg, Mark Soave, Patrizia Pannucci, Stephen J. Hill, and Jeanette Woolard.


Attributed to the synergetic coupling of the facet junction and the interfacial heterojunction that assures the effective charge separation, and the tremendous but physically separated reactive sites offered by layered MoS2 and highly‐exposed (001) facets of TiO2, respectively, the artificial Z‐scheme exhibits excellent photocatalytic performance in photodegradation tests. Moreover, the junctional plasmonic Au nanoclusters not only act as electron traps to promote the edge‐selective synthesis but also generate “hot electrons” to further boost photocatalytic performance. The Z‐scheme charge‐flow direction in the heterostructure and the roles of electrons and holes are comprehensively studied using in situ irradiated X‐ray photoelectron spectroscopy and photodegradation tests. This work offers a new insight into designing high‐performance Z‐scheme photocatalytic systems.The construction of photocatalytic systems that have strong redox capability, effective charge separation, and large reactive surfaces is of great scientific and practical interest. Herein, an edge‐connected 2D/2D Z‐scheme system that combines the facet junction and the interfacial heterojunction to achieve effective long‐range charge separation and large reactive surface exposure is designed and fabricated. The heterostructure is realized by the selective growth of 2D‐layered MoS 2/Au/TiO2 Z‐scheme photocatalytic system is fabricated by Au‐induced selective growth of MoS2 nanoflakes on the edge‐sites of TiO2 nanosheets. The ternary structure synergistically couples the facet junction and the heterojunction to separate the photogenerated charges in relays and maintains the highly exposed surfaces for redox reactions. The junctional Au nanoclusters generate “hot electrons” to further boost photocatalytic performance.An efficient MoS To boost the redox capability, constructing Z‐scheme heterojunction has proven to be the most effective strategy because it could take the synergistic effects of two semiconducting components to keep the high‐energy holes/electrons for redox reactions. The effective charge separation could be realized by facet junctions or heterojunctions, with facet junctions having weak but relatively long‐range charge separation while heterojunctions possessing strong but local charge separation. The large reactive surface area is commonly achieved by employing low‐dimensional, especially 2D nanomaterials. Irrespective of the progress made in each of these areas, it remains an extreme challenge to construct a 2D material‐based Z‐scheme photocatalytic system with a proper geometry so that all of the three merits exist in one unique catalytic system.Two of the biggest challenges confronting the world today are the global crises of clean energy supply and environmental pollution. To address these concerns, one of the most promising and sustainable technologies is sunlight‐assisted semiconductor‐based photocatalysis, which uses free solar energy to produce clean energy and for the removal of environmental pollutants.1 An i However, interfacial defects, functional groups, adsorbents, etc., could easily alter these interfacial properties, resulting in the formation of a Type II rather than a Z‐scheme heterojunction. In order to alleviate this uncertainty, minor differences between surface sites or crystal facets have been utilized for selectively constructing Z‐scheme heterostructures. It was found that some sites of a material surface or some crystal facets of a semiconductor were more favorable for the accumulation of electrons while some were prone to act as hole traps. This difference could be an intrinsic feature of the materials or induced by surface modification via ion or particle decoration. For example, CdS was selectively deposited at the electron transfer sites of g‐C3N4 to regulate the electron flow direction. Selective growth of CdS on (001) or (101) TiO2 facets was controlled by attaching/detaching F− ions. Core–shell heterojunctions were achieved by Au nanoparticle‐mediated growth. TiO2 hollow nanoboxes were utilized to force (101) facets to be exposed to the outmost of the cluster structures, forming TiO2(101)/g‐C3N4 contacted heterostructures. Cross‐stacked TiO2 nanostructures were used to expose (101) facets for fast and easy access to the precursors during photodeposition (PD) and to avoid the stacking growth of MoS2 on (001) facets. These strategies demonstrate great success in constructing different types of Z‐scheme heterojunctions, including randomly deposited, site‐selectively deposited, and facet‐selectively deposited Z‐schemes, but still fall short of obtaining high‐performance photocatalysts with both efficient charge separation and large reactive surface area. More specifically, in randomly or site‐selectively deposited Z‐scheme structures, the second semiconductor generally covers the surface of the first semiconductor in the format of nanoparticles or nanoclusters (NCs), so the increase of surface area for reduction (or oxidation) is at the expense of the decrease of the surface area for oxidation (or reduction). Furthermore, the spatial distance between these NCs is extremely short, which increases the charge recombination via environmental routes . Although the heterojunction itself has effective charge separation capability, the external recombination routes will compromise the overall charge separation efficiency. Consequently, such photocatalysts usually need sacrificial agents to guarantee their photocatalytic performance. In facet‐selectively deposited Z‐scheme structures, a complex morphology of the first semiconductor, which involves a complex fabrication process, is required to confine the access of precursors of the second semiconductor during the selective synthesis/construction. This confining mechanism, as well as the complex geometry, will also limit the access to the target molecules in photocatalytic applications, resulting in a significant decrease in the active surface area of the catalyst and thus the extent of its utilization.Interfacial design and selective synthesis are two major obstacles toward this goal. To obtain a Z‐scheme heterojunction for high redox capability, two constituent semiconductors must have well‐matched band alignment, intimate contact, and a dedicated charge transfer channel.2 Howe2 nanosheets (TNSs) with highly‐exposed (001) facets and layered MoS2 nanoflakes (NFs) are employed as two‐component materials. Au NCs are first decorated on the edge surfaces  facets) of TNSs via a diffusion and spatial confinement strategy. MoS2 is then selectively deposited on the Au NCs and TiO2 edge surfaces via a simple PD method. The resultant structure not only takes advantages of the combinative effect from the facet junction and heterojunction to maximize the charge separation and form a Z‐scheme structure but also physically separates the redox reactive surfaces, leaving the highly‐exposed (001) facets of 2D TNSs for oxidation and MoS2 for reduction reactions. While the Au NCs implanted between two semiconductors not only serve as a mediator to facilitate the fast migration of photogenerated electron holes at the heterointerface to ensure an effective Z‐scheme charge transfer but also act as a source of “hot electron” injection to improve the photocatalytic performance. Such a photocatalyst system is extremely beneficial for photodegradation applications that have diverse and unknown pollutants.Herein, we design a 2D material‐based Z‐scheme photocatalyst that constructively couples the facet junction and heterojunction to simultaneously achieve high redox capability, efficient charge separation, and large reactive surface area. 2D anatase TiO22.12/Au/TiO2 (MS/Au/T) heterogeneous photocatalyst. The schematic design and stepwise fabrication process are illustrated in Figure  In the second step, Au atoms and fine nanoparticles were dispersed on the TNSs via solution phase synthesis. The dispersed Au particles were then turned into selectively deposited Au NCs on the edge‐sites, that is, (101) facets of TNSs after controlled calcination treatment to obtain Au/TiO2 (Au/T) heterostructures. Mechanistically, Au ions were first reduced into Au atoms or small particles that were randomly distributed over the TNSs surfaces and then transformed to NCs and selectively accumulated on (101) facets via diffusion and spatial confinement mechanism. In the last step, MoS2 was selectively deposited via a modified PD method at room temperature. Au/T was initially mixed with an aqueous solution containing MoS42− and then irradiated with simulated solar light. Interestingly, it was found that MoS2 preferably grew on Au NCs first, then on (101) facets of TNSs to form ternary MS/Au/T heterostructures. Notably, Au played a critical role in the PD process, because it offered strong affinity with S, trapped electrons from TiO2 (101) facets, and produced more electrons via localized surface plasmon resonance (LSPR). Therefore, it accumulated more electrons to amplify the potential difference between (001) and (101) facets of TNSs, and thus promoted the selective PD of MoS2 on Au NCs and the edges of TNSs.The idea of junction coupling was realized by constructing an edge‐connected MoSn Figure 13 In  Since the work function of Au is larger than that of TiO2, the accumulated photogenerated electrons at the interface transfer from TiO2 (101) facets to Au NCs, establishing a consecutive electron flow path: TiO2 (001) facet → TiO2 (101) facet → Au NCs  facets with the holes from the valence band (VB) of MoS2, forming a Z‐scheme charge transfer that leaves the electrons in CB of MoS2 and holes in VB of TiO2 (001) facets with higher energies for redox reactions . This Z‐scheme boosts the charge separation to have a higher photocatalytic efficiency and can be applied in various catalytic reactions with high redox potentials, owing to its well‐retained strong redox ability. Particularly, in our system, the photoinduced holes mainly accumulate on the TiO2 (001) facets with a large area, which offer highly‐exposed oxidation sites and thus promote the photocatalytic reaction. In addition, the spatially separated reduction (MoS2) and oxidation (TiO2 [001] facets) active sites allow the photocatalyst system to participate in reduction and oxidation reactions simultaneously, beneficial for the photodegradation applications that have diverse and unknown pollutants.To illustrate the charge carrier's migration principle, the energy band diagrams of TNSs, Au/T, and MS/Au/T are shown in Figure 15 Sins Figure , which f2, respectively, confirming that the synthesized TNSs have highly‐exposed (001) facets and thin (101) facets. Figure  The transmission electron microscopy (TEM) image in Figure 2 NFs were intimately deposited in a layered manner via photo‐assisted nucleation and growth process at room temperature. Red‐dotted line in Figure 2 NFs were thin and immature crystalline structures, but they formed the shell to cover the Au NCs (yellow circle) pre‐deposited on TiO2 (101) facets. A clearer HRTEM image showing two distinct interfaces of TiO2/Au and Au/MoS2 in MS/Au/T can be found in Figure The morphologies of TNSs, Au/T, and MS/Au/T were examined by scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HRTEM) analysis. As depicted in Figure 2,16 res2, which well matched the reference pattern (JCPDS 21–1272). Anatase TNSs were well‐retained without any phase change even after the deposition of Au NCs and MoS2 NFs. The diffraction peaks observed at 38.1°, 44.3°, 64.4°, and 77.5° in Au/T photocatalyst could be attributed to FCC Au (JCPDS 04–0784). The distinct (004) diffraction peak of TNSs indicates the dominant crystal growth along the (001) direction, which is typical for anatase TiO2 with highly‐exposed (001) facets. However, no obvious signals of MoS2 were observed in the XRD pattern of the MS/Au/T photocatalyst. This could be due to its amorphous‐like structure or poor crystallinity and thin‐layered 2D morphology or high dispersion on very small but crystalline Au NCs. The Raman studies further demonstrated this conjecture. As shown in Figure −1 could be respectively assigned to Eg, B1g, A1g, and Eg anatase tetragonal vibration modes of TiO2. The observed shift at 153 cm−1 corresponding to the Eg Raman mode of Au/T confirmed a strong interfacial contact and electronic interaction between TiO2 and Au. However, no characteristic peaks belonging to E12g and A1g of 2H‐MoS2 were found in the MS/Au/T spectrum, which confirmed the amorphous‐like structure and poor crystallinity of MoS2. As experimental evidence, the presence of MoS2 was proved by X‐ray photoelectron spectroscopy (XPS). The XPS spectrum of MS/Au/T exhibited two characteristic peaks at 229.04 and 232.14 eV  and Raman spectroscopy. The obtained patterns of TNSs, Au/T, and MS/Au/T are shown in Figure 21–1272).16 Anap displayed obvious differences among TNSs, Au/T, and MS/Au/T. For Au/T, the BEs of Ti 2p3/2 and Ti 2p1/2 were respectively 458.47 and 464.17 eV, with splitting energy of 5.7 eV, manifesting the presence of tetragonal Ti4+, but both peaks were 0.11 eV lower than those of TNSs. This negative shift suggests strong interfacial interaction between Au and TiO2. After depositing MoS2 on Au/T, the BEs of Ti 2p showed an obvious positive shift (0.35 eV) compared to those of Au/T, which also suggests the strong interfacial interaction and indicates electrons moving out from TiO2 (into Au NCs). The XPS spectra of O 1s in TNSs, Au/T, and MS/Au/T can all be de‐convoluted into one major and two minor peaks , surface oxygen vacancy (Ov) and absorbed water molecules (Ow), respectively. The OL peak in Au/T exhibited a negative and positive shift compared to that in TNSs and MS/Au/T, respectively, which is consistent with the analysis of Ti 2p spectrum as described above. According to the XPS peak area, the content of Ov in the proportion of three oxygen peaks in TNSs, Au/T, and MS/Au/T was 3.5%, 6%, and 10.1%  and 86.6 eV (Au 4f5/2)  MoS2 primarily nucleated on the Au NCs and grew up into small‐size NFs, shown as small bumps or shells in Figure 2 NFs expanded their growth to cover the (101) facets of TNSs, as shown in Figure 2 turned to deposit on the (001) facets of TNSs, as clearly shown in the BF‐HRTEM  and (101) facets, resulted in the accumulation of electrons on (101) facets. Due to the intimate contact between Au NCs and TNSs, as well as the lower Fermi level of Au compared to TiO2, the electrons preferred to gather on the Au NCs  facets of TNSs. Because of this extended growth pattern, a direct Z‐scheme charge transfer  facets and MoS2 due to their intimate contact. However, due to the strong electron trapping capability of Au NCs, TiO2 → Au → MoS2 Z‐scheme pattern still dominates the charge transfer process. After the surface of (101) facets were fully covered (only ≈6 nm wide), further growth of MoS2 could only occur on the (001) facets. In short, the selectivity of the growth is based on the electron density and the availability of the exposed surface area. Experimentally, it is interesting to note that the low initial concentration of MoS42− and shorter PD time are more favorable for selective and controlled growth.The mechanism of nucleation and growth of MoS) facets,15 ress Figure . In addi2.32 on (001) facets should be minimized because it decreases the oxidation surface area and forms a Type II structure  MS/Au/T. For example, 10% MS/Au/T represents the set of samples synthesized at a fixed MoS42− concentration that yields 10% MoS2 if all MoS42− are converted into MoS2. Figure tC/0C for 10% MS/Au/T catalysts with PD = 1, 2, 4, 5, and 6 h, respectively, where Ct is the MB concentration at irradiation time t, and C0 is the concentration at absorption equilibrium of the photocatalyst samples before irradiation. With the increase of PD time, the degradation rate increased first, until reaching the maximum value of 70.3% at PD = 5 h, and then decreased. The corresponding pseudo‐first‐order constant k  is shown in Figure 2, which increased with PD time. As the PD time approached to ≈5 h, MoS2 fully covered the Au NCs and TiO2 (101) facets to form the proposed Z‐scheme that exhibited the best photocatalytic performance. However, as the PD time further increased, MoS2 started to grow on TiO2 (001) facets and disturbed the Z‐scheme charge transfer, leading to a decreased photocatalytic efficiency.Photocatalytic MB degradation experiments were then performed for the optimization of MS/Au/T photocatalysts under UV light illumination (360–370 nm) for 90 min. Catalyst samples were prepared at a fixed initial concentration of MoS42− also had a large impact on the growth of MoS2 and thus affected the photocatalytic efficiency. As shown in Figure k of MS/Au/T samples with different mass ratios of MoS2, which were synthesized at different initial concentrations of MoS42− but for the same PD time. For PD = 4, 6, and 8 h, when MoS2 was less than 10%, k increased with the increase of the MoS2 mass ratio. However, as MoS2 was greater than 10%, k decreased with the increase of MoS2. This observation could be explained as: when MoS2 was less than 10%, the photocatalytic efficiency was limited by the amount of MoS2 due to the insufficient growth of MoS2 on Au NCs and active TiO2 (101) facets. On the other hand, when MoS2 was larger than 10%, it was much easier and faster to grow on TiO2 (001) facets at a higher initial concentration of MoS42−, which changed the charge transfer mechanism from Z‐scheme to Type II  facets and holes on VB of MoS2, respectively, both characterized by lower redox energy. Moreover, the excess growth of MoS2 on TiO2 (001) facets covered the active sites of holes for the catalytic reaction, further resulting in a low photocatalytic efficiency. However, at PD = 2 h, the values of k for 5% and 10% were almost the same, indicating that the growth of MoS2 was not enough, as explained before. After examining the overall trend of these curves, we have determined that 10% MoS2 is the optimum value in our designed experiment. This value could be affected by the morphology or exposed area ratio between (101) and (001) facets. The optimal k values for different mass ratios of MoS2 were summarized and shown in Figure k (0.0144 min−1).In addition to the PD time, the initial concentration of MoS2.4Figure p3/2) and 464.52 eV (Ti 2p1/2), assigned to the characteristics Ti4+ species in TiO2. Under UV light irradiation, a positive shift of 0.1 eV was observed in the BEs of Ti 2p, indicating a decrease in electron density. Based on the electrostatic shielding effect, more outer electrons resulted in a weaker BE, illustrating that the photoinduced electrons were transferred out of TiO2. Other two characteristic peaks for Mo4+ species in MoS2 at 229.04 eV (Mo 3d5/2) and 232.14 eV (Mo 3d3/2) were observed in the absence of light, which displayed a negative shift of 0.22 eV upon the light illumination, suggesting the increase of electron density on MoS2 surface  analysis of the prepared MS/Au/T photocatalyst were conducted. As shown in e Figure . The opp2, are both exhibited for all of the three samples. Compared to TiO2 and Au/T samples, MS/Au/T has an emission quenching effect at 397 nm but enhanced emission at 465 nm, suggesting a fast trapping or transfer process of free carriers and more surface‐trapped holes in the hetero‐structured catalyst. This is very consistent with the Z‐scheme charge flow, in which the holes on TiO2 are preserved but electrons are transferred. Since the photocatalytic reactions are relatively slow processes, the surface‐trapped carriers are more important than free carriers. Time‐resolved FL decay at the emission wavelength of 465 nm was then measured and fitted with a bi‐exponential function (Supporting Information) to reveal more dynamics of surface‐trapped holes. As displayed in Figure 2 surface holes, which was confirmed by the calculated average lifetime τ in the inserted table. All of these results demonstrated the Z‐scheme charge transfer mechanism.To probe the charge separation behavior, photocurrent transients were performed for TNSs, Au/T, and MS/Au/T, respectively. As indicated in Figure 2,33 are+), and superoxide radicals (•O2−), respectively. After introducing IPA, AO, and BQ in MB solution, k decreased from 0.0144 min−1 to 0.005 min−1, 0.098 min−1, and 0.0135 min−1, respectively, as shown in Figure +, as well as the negligible effect of •O2− on MB degradation. As one of the major reactive species in photocatalytic reaction, •OH radicals are mainly formed via direct oxidation of OH− or H2O by holes or via multiple reduction reactions from •O2− by electrons. Since •O2− had little impact on MB degradation, the oxidation of OH− or H2O became the only way to produce •OH radicals. In the synthesized MS/Au/T photocatalyst, the photogenerated holes from the VB of MoS2 (1.2 V vs NHE) are incapable of oxidizing OH− or H2O due to their more negative potential than that of OH−/•OH (2.4 V vs NHE) or H2O/•OH (2.64 V vs NHE), as indicated in Figure 2 , ammonium oxalate (AO), and benzoquinone (BQ) were employed as the scavengers for hydroxyl radicals (•OH), holes  as an electron sink and performed a comparative test for MB degradation with an MS/Au/T sample in the presence of limited (dissolved O2 in solution) and rich O2 (under a continuous flow of O2 during the test) environment. The results are shown in Figure In many site‐selectively and randomly grown Z‐scheme photocatalytic systems, the photogenerated electrons and holes are separated locally and have many routes to recombine, so a sacrificial agent is usually needed to consume one type of charges (electrons or holes) to guarantee the effective photocatalytic performance of the other type of charges (holes or electrons). In our system, since the holes were proved as the charge carriers to participate in MB degradation, the addition of an electron sink was expected to further improve the photocatalytic activity. Hence, we chose oxygen  was further compared with pristine TNSs, Au/T, and 10% MS/T by MB degradation experiments. As indicated in Figure 2.52− into intermediate molecules for further oxidative degradation. The reactive species experiments were conducted with the same scavengers as employed in the MB degradation experiment. The corresponding rate constants were calculated and shown in Figure k slightly decreased, indicating the little effect of holes in the experiment. As IPA and BQ were introduced, k dropped significantly, demonstrating that both •OH and •O2− were the major reactive species. In general, •O2− could reduce pollutants directly or generate •OH via multiple reactions to oxidize the pollutants. Since •OH radicals generated from multiple reactions from •O2− was very limited as proven by the above MB degradation, the impact of the BQ test suggested that •O2− could directly reduce electron‐deficient compounds bearing nitro groups (4‐NP) into intermediates, which was further oxidized by •OH.In the designed Z‐scheme heterojunction, the role of holes with high oxidation ability was demonstrated in MB degradation. To investigate the role of electrons in the system, the photocatalytic degradation of 4‐nitrophenol (4‐NP) was performed, because 4‐NP could be oxidized by •OH and also be reduced by •O but generate “hot electrons” participating in the chemical reactions to improve the photocatalytic efficiency. To demonstrate this effect in our system, a comparison test for 4‐NP degradation with 10% MS/Au/T photocatalyst was performed under UV and simulated solar light. As indicated in Figure  generating “hot electrons” in the surface plasma (SP) state. These “hot electrons” were then transferred to the CBs of the neighboring TiO2 and MoS2, respectively. The extra electrons on the CB of MoS2 reacted with the dissolved O2 to generate more •O2−, promoting the overall degradation rate of 4‐NP.It is well known that the LSPR of Au could not only broaden the visible light absorption40 but4+ 3d decreased by 0.11 eV under simulated solar light compared to the value measured under UV light. This negative shift demonstrated the increase in the electron density, indicating the injection of “hot electrons” from Au NCs to MoS2. Hence, Au NCs played dual functions, not only acting as charge mediators in the Z‐scheme structure to boost the interfacial charge recombination but also generating excess “hot electrons” to improve the photocatalytic performance.The described mechanism was proved by comparing the ISI‐XPS patterns of Mo element under UV and solar simulated light, respectively. As shown in Figure 2 to Au NCs due to the potential difference between TiO2 and Au. The other one is from Au NCs to TiO2 due to the “hot electrons” injection. These two routes counteract each other, compromising the charge separation efficiency and leading to only a slight improvement of photocatalytic performance of Au/T than TNSs. This conjecture is evidenced by the nearly unchanged BEs of Ti 2p in ISI‐XPS measurements under UV and solar light illumination  hydrothermal preparation of TNSs with highly‐exposed (001) facets; ii) selective deposition of Au NCs on the edge‐sites of TNSs; iii) selective PD of MoS2 NFs on Au NCs and (101) facets of TNSs. The edge‐selective growth of MoS2 was realized and promoted by Au NCs, which could trap electrons from TNSs and generated excess electrons via the LSPR effect for efficient photoreduction, and offered strong affinity to S for effective MoS2 nucleation. The growth and morphological evolution of MoS2 could be categorized into three stages: site‐selective nucleation (on Au NCs), facet‐selective extension  facets), and random growth (over TiO2 (001) facets). It was found that a high precursor concentration and a long PD time promoted random growth. The optimal conditions were found to be a 10% MoS2 mass ratio and a 5 h PD time, which could be associated with the morphology of TiO2.We have designed an efficient MoS2, forming a Z‐scheme charge transfer route. Photocurrent transients and FL measurements further demonstrated the proposed Z‐scheme mechanism. Since this Z‐scheme was built on the TNS (101) facets, a synergetic coupling of the facet junction and the heterojunction was achieved to separate the photogenerated charges in relays. This structure not only suppressed the charge recombination in the system but also maintained the highly exposed surface to the utmost extent. Consequently, the highly exposed surfaces of TNSs and MoS2 NFs offered tremendous active sites for redox reactions. The spatial separation of TNSs and MoS2 NFs endowed the bifunctional system to participate in different photocatalytic reactions simultaneously. Au NCs in the proposed system served two purposes: constructing the heterojunction and accelerating the redox reactions by supplying “hot electrons”. As a result, the system demonstrated its effectiveness and efficiency in the photodegradation of organic pollutants without involving any sacrificial agents. This work sheds new light on the possibility of designing and selectively fabricating other 2D/2D Z‐scheme photocatalysts using this novel photocatalyst prototype in the future.ISI‐XPS measurements validated that the photogenerated electrons in TNSs were transferred to Au NCs and recombined with the holes generated in MoS416H36O4Ti, >97%), hydrofluoric acid , ammonium tetrathiomolybdate , and 4‐nitrophenol  were procured from Sigma Aldrich. Gold (III) chloride trihydrate (III) , urea , and methylene blue (C16H18ClN3S) were purchased from Merck. All the reagents were used as received without further purification. The water used throughout the experiments was purified by a Milli‐Q system.Analytical grade tetrabutyl titanate  water, and then air dried at 80 °C in an oven for 12 h.Anatase TNSs were synthesized by hydrothermal method proposed by Han et al.13 In  In the typical synthesis, the as‐prepared anatase TNSs (100 mg) were well dispersed in 10 mL DI water with 60 min in water bath ultra‐sonication followed by 30 min vigorous stirring. Then, 4.2 mm of HAuCl4 4H2O was added to the above solution ensuring the random deposition of Au on TNSs. Later, urea was introduced with an amount equivalent to the hundred times than that of the Au precursor to reduce the Au ions. The formed bright‐yellow mixture was thermostatically heated at 80 °C in an oil bath under robust stirring for 3 h. After washing with ethanol and DI water followed by centrifugation several times, the randomly‐deposited Au/TiO2 with 4 wt% of Au loading was obtained. After drying the randomly deposited Au/TiO2 in a vacuum oven at 90 °C for 3 h, the collected powder was then calcinated from room temperature to 400 °C in an Ar atmosphere under a flow rate of 40 mL min−1 with a heating rate of 3 °C min−1 for 3 h to obtained the selectively edge‐deposited Au/TiO2.Randomly deposited Au/TNSs were synthesized by an aqueous phase process with urea as a basifier.14b In2/Au/TiO2 photocatalyst was synthesized by a facile one‐step photo‐deposition method. In the typical synthesis, 80 mg of as‐synthesized Au/TiO2 powder was well dispersed in 30 mL of DI water by 30 min ultrasonication. Meanwhile, a calculated amount of (NH4)2MoS4 was dissolved in 10 mL of DI water, followed by 30 min of vigorous stirring. Then, the prepared (NH4)2MoS4 solution was added into Au/ TiO2 suspension dropwise under continuous stirring; subsequently, 4 mL of ethanol was added to the above mixture. The resultant suspension was continuously stirred and bubbled with Ar gas in dark for 30 min to completely remove the dissolved oxygen. Next, the mixture was irradiated by a solar simulator with a 1000 W Xenon short‐arc lamp equipped with an AM1.5G filter for a specific photodeposition time. The sample was then centrifuged and washed with DI water for several times, followed by drying in a heating oven at 70 °C overnight  and a confocal Raman microscopy spectrometer  under 532 nm laser light. The detailed morphologies of the samples were studied with a field emission scanning electron microscope (JEOL JSM‐7610F FEG‐SEM) and a TEM (FEI Tecnai TEM 200 kV). The presence and distribution of elements were examined by energy‐dispersive X‐ray spectroscopy (EDS) . The BE of C 1s (284.6 eV) was used to calibrate the BE axis. The ISI‐XPS was performed on the same instrument with a 300 W Xenon light  equipped with UV and visible light bandpass filter, placed at 10 cm away from the target samples during the analysis.The crystalline structures of the photocatalysts were characterized by an XRD , using CuKFL test was conducted using an FS5 spectrometer (Edinburgh Instruments Ltd.). Steady‐state FL spectra were measured under an excitation wavelength at 330 nm. Time‐resolved FL decay was measured with an excitation wavelength at 365 nm and an emission wavelength at 465 nm.The photocatalytic MB degradation was carried out in a 200 mL of glass beaker under the irradiation of a flat UV lamp . Before irradiation, 20 mg of the prepared photocatalyst was uniformly dispersed in 70 mL of 10 ppm MB aqueous solution kept in dark under magnetic stirring for 30 min to reach an adsorption/desorption equilibrium. The suspension was then irradiated with the UV light under continuously stirring. After given intervals of time, ≈2 mL aliquots were sampled from the reaction beaker with a syringe, centrifuged (10 000 rpm for 8 min), and filtered to remove any residual catalysts. A UV/vis/NIR spectrophotometer (PerkinElmer LAMBDA 1050) was used to measure the absorption spectra of MB aqueous solution as a function of the irradiation time.−1, followed by ultrasonication of 5 min to get the homogenous suspension. Before switching on the lamp, oxygen was bubbled into the suspension for 20 min in dark under magnetic stirring to assure the formation of an adsorption/desorption equilibrium. After that, the solar simulator was turned‐on and oxygen was continuously circulated into the suspension throughout the experiment. After given intervals of time, ≈2 mL aliquots were sampled from the reaction beaker with a syringe, centrifuged (10 000 rpm for 8 min), and filtered to remove any residual catalysts. The filtrate was analyzed with a Thermo Scientific HPLC system (Dionex UltiMate 3000 Photodiode Array Detector).The photocatalytic degradation of 4‐NP was tested with an irradiation system, which consisted of a tunable solar simulator (1000 W Xenon short arc lamp equipped with AM1.5G Filter), a 400 mL glass beaker with a quartz lid, and an oxygen gas supply. The radiation intensity reaching the surface of the prepared suspension was measured using a radiometer (Delta Ohm 9721) and the matching probe before starting the experiment. Before each set of experiments/cycle, the catalysts were added progressively until the final transmitted radiation intensity reaching the bottom of the beaker went down to 5% of its initial radiation. The pre‐measured specific amount of catalyst was added to 250 mL of 4‐NP suspension with the concentration of 5 mg L2 for the Mott–Schottky experiment, and 1.8 cm2 for photocurrent transients). 0.5 m Na2SO4 solution was filled in the quartz cell as the electrolyte. Mott–Schottky experiment was conducted at a potential step of 50 mV at a constant frequency of 10 kHz. Photocurrent experiment was recorded at a potential of 1 V under the irradiation of a 50 W LED lamp with a wavelength of 365 nm.Photoelectrochemical measurements were carried out on a PGSTAT302N potentiostat (Metrohm Autolab) in a standard three‐electrode cell. A platinum electrode was employed as the counter electrode, and Ag/AgCl electrode was used as the reference electrode. The as‐prepared sample films were coated on fluorine doped tin oxide glass slides as working electrodes (coating area is 1 cmThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The total of applicants not reporting their race was fixed to “91 (12.5%) did not indicate race and 17 (2.3%) preferred not to answer.” An error in the color coding for Figure 3 has also been corrected. This article has been corrected.1In the Original Investigation titled “Current Communication Practices Between Obstetrics and Gynecology Residency Applicants and Program Directors,”


Sixty‐six PvCO2 samples were obtained, and there was a high correlation between PvCO2 and PaCO2 . Regarding type 2 respiratory failure, there was a high correlation between EtCO2 and PaCO2 (r = 0.81). The Bland–Altman analysis between PaCO2 and EtCO2 revealed a bias of 5.7 mmHg, with limits of agreement ranging from −5.1 mmHg to 16.5 mmHg. In contrast, the analysis between PaCO2 and PvCO2 revealed a bias of −6.8 mmHg, and the limits of agreement ranged from −22.13 mmHg to 8.53 mmHg.A total of 100 samples were included that comprised 67 men (67%). The mean age of the subjects was 77 ± 13 years. Chronic obstructive pulmonary disease (COPD) (43%) was the most common disease. There was a high correlation between EtCO2 measured by CapnoEye® was significantly correlated to PaCO2 levels in patients with respiratory diseases. Moreover, CapnoEye® may be more useful for predicting hypercapnia conditions in which respiratory diseases are compared with measure PvCO2.EtCO 2 measured by CapnoEye® was significantly correlated to PaCO2 levels in patients with respiratory diseases. While type 1 patients displayed a moderate correlation, type 2 patients demonstrated a high correlation between EtCO2 and PaCO2. In contrast, the correlation between PvCO2 and PaCO2 was moderate for both type 1 and type 2. CapnoEye® may be more useful for predicting hypercapnia conditions in which respiratory diseases are compared with measure PvCO2.EtCO ABGarterial blood gasCOPDchronic obstructive pulmonary disease2EtCOend‐tidal carbon dioxideICUintensive care unit2PaCOpartial pressure of arterial carbon dioxide2PaOpartial pressure of arterial oxygen2PvCOpartial pressure of venous carbon dioxide12) is <60 mmHg and/or the partial pressure of arterial carbon dioxide (PaCO2) is >45 mmHg. Respiratory failure is classified according to blood gas abnormalities into types 1 and 2. Type 1 (hypoxemic) respiratory failure is a disorder of the respiratory system in which the PaO2 and PaCO2 are ≤60 mmHg and <45 mmHg, respectively, due to respiratory dysfunction. A PaCO2 > 45 mmHg is defined as type 2 (hypercapnic) respiratory failure. Hypoxemia is a common condition and can be attributed to ventilation failure.Respiratory failure is a clinical condition characterized by the failure of the respiratory system to maintain its major function, that is, gas exchange, in which the partial pressure of arterial oxygen  assessment is essential to confirm the diagnosis of respiratory failure, and frequent measurements are necessary to confirm the respiratory status during the course of treatment. An American Thoracic Society/European Respiratory Society position paper reported on ABG analysis as the preferred method for determining the need for oxygen, as it includes acid–base information.The monitoring of respiratory condition necessitates the most non‐invasive technique in the perioperative period and the intensive care unit (ICU).2) is another non‐invasive method for estimating PaCO2. EtCO2 is generally measured as biological information in patients in the operating room or in the ICU with controlled ventilation. However, it is not usually measured in general wards or laboratories.2.The measurement of end‐tidal carbon dioxide  can non‐invasively measure EtCO2 levels. CapnoEye® was used to measure EtCO2 and PaCO2 in patients with type 1 and 2 respiratory failure. We aimed to calculate and evaluate the correlation coefficients and their measurement accuracies. We also intended to compare differences between venous and arterial carbon dioxide levels only in patients who simultaneously underwent venous blood gas measurements. Furthermore, we also aimed to compare the efficacy of EtCO2 and PvCO2 in predicting PaCO2 levels.We aimed to evaluate the accuracy and efficacy of the novel portable capnometer for predicting PaCO22 was measured from February 2017 to December 2019. Simultaneously, we collected arterial blood gas sampling to measure the PaCO2. Moreover, we only compared the venous carbon dioxide (PvCO2) and PaCO2 values in patients who had underwent the sampling concurrently. These samples were collected under similar conditions at a particular time. EtCO2 was measured using the CapnoEye® . The measured data were compared overall and between the two groups. We collected 66 samples of PvCO2 (34 patients with type 1 and 32 patients with type 2 respiratory failure). The PvCO2 and EtCO2 data were also compared overall and between the groups.We collected a total of 100 samples of EtCO2 and PaCO2 and between PvCO2 and PaCO2 using Pearson's moment correlation coefficient in patients with type 1 and type 2 respiratory failure and both groups overall. We also analyzed the agreement between EtCO2 and PaCO2 and between PvCO2 and PaCO2 using Bland–Altman analysis. Moreover, we calculated the estimated bias  and precision  in subjects with type 1 and type 2 respiratory failure and both groups overall. Data are presented as the mean (standard deviation). Descriptive data are presented as the median, frequency, and percentage. Statistical analyses were performed using JMP 14 .We analyzed the correlation between EtCO2.2This study was conducted in accordance with the tenets of the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Clinical Investigation for the National Center for Global Health and Medicine . All subjects provided informed consent for their inclusion in this study.32, EtCO2, and PvCO2 were 74 ± 13 years, 22.0 ± 4.6, 47.2 ± 11.8 mmHg, 41.5 ± 10.1 mmHg, and 53.4 ± 13.2 mmHg, respectively. Table Table 2 and PaCO2 in all patients . The correlation coefficient was 0.883, and we observed a high positive correlation. . Figure 2 and PaCO2 in all patients , with a correlation coefficient of 0.814, which demonstrated a high positive correlation . Next, we separated the data into two categories, Type 1 and Type 2, and illustrated the correlations between them in the figures  displayed a moderate correlation (r = 0.47), type 2 patients (n = 49) demonstrated a high correlation (r = 0.81) between EtCO2 and PaCO2. In contrast, the correlation between PvCO2 and PaCO2 was moderate for both type 1 (n = 34) and type 2 (n = 32) .No specific technical problems were encountered in these measurements. Figure s Figure . While t2 and EtCO2 and between PaCO2 and PvCO2. The Bland–Altman analysis between PaCO2 and EtCO2 revealed a bias of 5.7 mmHg, with limits of agreement (bias ± 1.96 SD) ranging from −5.1 mmHg to 16.5 mmHg. However, it also revealed a bias of −6.8 mmHg between PaCO2 and PvCO2, with limits of agreement (bias ± 1.96 SD) ranging from −22.13 mmHg to 8.53 mmHg.Figure 42 measured using the novel portable capnometer was significantly correlated with PaCO2 levels in patients with respiratory diseases. The correlation coefficient between EtCO2 and PaCO2 was 0.883, thus indicating a positive correlation . Moreover, the correlation coefficient between PvCO2 and PaCO2 was 0.814 and also indicated a positive correlation . The Bland–Altman analysis demonstrated good agreement and tolerance between the two variables. Furthermore, EtCO2 measured using the novel tool may be more useful for predicting hypercapnia conditions in which respiratory diseases are compared with measure PvCO2. However, the limits of agreement against both groups were wide. Therefore, care providers must pay attention to the characteristics and errors of these devices.In our study, EtCO2 has been measured for the non‐invasive estimation of PaCO2. EtCO2 is commonly measured in the closed circuit in patients undergoing mechanical ventilation. Therefore, it has been most often used as a non‐invasive substitute for PaCO2 in anesthesia, anesthetic recovery, and intensive care.2 would more accurately predict PaCO2. Without significant changes in cardiac output or in the ventilation/perfusion ratio, PaCO2 can be estimated with clinically acceptable sensitivity and specificity than EtCO2.2 is challenging in patients who are not intubated. This can be attributed to the difficulty to collect pure respiratory gas.Conventionally, EtCO2) for determining hypoxemia, measuring SpO2 alone is not sufficient to detect hyperventilation or hypoventilation. Particularly with the administration of supplemental oxygen, patients can display adequate arterial saturation during hypoventilation.2 retention in patients with respiratory failure. Nonetheless, no devices have been identified to easily monitor CO2 retention in general wards and outpatient clinics. Recently developed transportable capnometers can measure EtCO2 easily and non‐invasively in patients who are not intubated. Moreover, a recent study demonstrated that they could provide reliable EtCO2 values compared to PaCO2 in patients undergoing general anesthesia.Despite the usefulness of monitoring oxygen saturation  lower than PaCO2. We also confirmed a high correlation between EtCO2 and PaCO2 in patients with type 1 and 2 respiratory failure. In other words, the non‐invasive estimation of PaCO2 by measuring EtCO2 using CapnoEye® is clinically useful. The measurement of EtCO2 was not associated with any complications. In addition, the patient burden was extremely small. It is necessary to wait for few minutes for a 0‐point correction before the measurement. However, the measurement process is easy. The measurement only required disposable mouthpieces, and CapnoEye® was able to measure EtCO2 at a low price. However, its disadvantage was the inability to continuously monitor and record the parameter. While this measurement device is simple, based on a proprietary algorithm, and is easily measured and carried around, it does not enable offline storage of measurement data; therefore, it requires the user to take notes or pictures of the displayed data on the screen. It could not be used for patients with impaired consciousness or cognitive decline who were unable to respond to our instructions.CapnoEye® can measure EtCO2 was correlated with PaCO2 higher than PvCO2, particularly in type 2 respiratory failure. The measurement of PvCO2 instead of PaCO2 would result in data discrepancies in patients with chronic respiratory failure, as in our patient cohort. The effects of cardiac output and tissue oxygen consumption may have caused differences in the venous and arterial CO2 levels in patients with chronic respiratory failure, compared with known reports. Therefore, our findings suggest that the predicate of arterial blood gas analysis likely preferred EtCO2 to PvCO2 in patients with chronic respiratory failure, predominantly type 2 respiratory failure. Type 2 monitoring is more important in actual clinical practice. This highlights the significance of performing non‐invasive monitoring in patients with a tendency for chronic CO2 retention.A previous study reported that arterial blood gas analysis during the acute exacerbation of chronic obstructive pulmonary disease could be substituted by venous blood gas analysis.52 in patients who were alert and breathed spontaneously. Thus, it was unsuitable for patients who did not spontaneously breathe, were unable to respond to our instructions, or demonstrated poor spontaneous breathing, such as those with neuromuscular diseases. Fourth, some patients with type 2 respiratory failure underwent repeated measurements, which may be a source of bias. However, it is unknown whether EtCO2 measurements using this novel device in patients with refractory failure and spontaneous breathing can be considered an alternative to PaCO2 measurements that use arterial blood gas analysis in clinical settings.Our study had several limitations. First, the Bland–Altman analysis demonstrated that the limits of agreement against both groups were wide. Therefore, care providers must pay attention to the characteristics and errors of these devices. Second, this was a single‐center retrospective study comprising a small sample size. Third, the CapnoEye® measurement changes depending on the patient's breathing pattern. Therefore, it could only evaluate EtCO62 measuring instruments have displayed a high correlation with PaCO2 and are clinically applied as a substitute for PaCO2. The novel portable capnometer can measure EtCO2 in a simple and non‐invasive way. EtCO2 measured using CapnoEye® demonstrated a positive, strong, and statistically significant correlation with PaCO2 levels in patients with respiratory diseases. Furthermore, EtCO2 measured using the novel tool may be more useful for predicting hypercapnia conditions in which respiratory diseases are compared to measure PvCO2.Considering the improved accuracy of measuring instruments, EtCOWe intend to conduct future studies to confirm the usefulness of these measurements, particularly for type 2 patients in primary care.None.This study was conducted in accordance with the tenets of the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Clinical Investigation for the National Center for Global Health and Medicine . Written informed consent was obtained from all patients.MS conceptualized and designed the study, drafted the initial manuscript, and reviewed and revised the manuscript. MS, SF, KS, and KT entered and collected data into the database. MS and SF contributed significantly to managing the data and MS to the statistical analysis. All authors revised the article critically for important intellectual content, gave their final approval of the version to be published, and agreed to be accountable for all aspects of the work.


It is revealed that in the Co/BiFeO3 heterostructure excited by femtosecond laser pulses, the magnetization precession amplitude follows a sinusoidal dependence on the laser polarization direction. This nonthermal control of coherent magnetization rotation is attributed to the optical rectification effect in the BiFeO3 layer, which yields a FE polarization depending on the light polarization, and the subsequent modulation of magnetic energy in Co by the electrostriction‐induced strain. This work demonstrates an effective route to nonthermally manipulate the ultrafast magnetization dynamics in metallic ferromagnets.Coherent optical control of the magnetization in ferromagnetic (FM) mediums using ultrafast nonthermal effect paves a promising avenue to improve the speed and repetition rate of the magnetization manipulation. Whereas previously, only heat‐induced or helicity‐dependent magnetization dynamics are demonstrated in metallic ferromagnets. Here, the linearly‐polarized light control of magnetization is demonstrated in FM Co coupled with ferroelectric (FE) BiFeO 3. The laser irradiation on the Co/BiFeO3 heterostructure leads to a sinusoidal dependence of ultrafast magnetic torque impinged upon the magnetization precession on the light polarization direction.A new strategy of ultrafast nonthermal control of magnetization is adopted by coupling the metallic ferromagnet with the ferroelectric material. It utilizes the advantages of pronounced optical rectification effect and ferroelastic response in BiFeO The magnetization dynamics induced by the non‐thermal optical effect usually show a strong dependence on the pump light polarization.Nonthermal optical stimulation of coherent magnetization dynamics has great value for fast‐speed information storage devices employing the magnetic medium owing to its negligible heat accumulation and high repetition rate.3, 4 and it can also induce the optical spin transfer torque as a result of the injection of spin‐polarized carriers in the ferromagnetic (FM) semiconductor involving the photon absorption. For these effects, the left‐handed and right‐handed circular‐polarized light pulses trigger transient magnetic moments or spin‐polarized electrons with opposite orientations. The non‐thermal excitation mechanisms correlated with the linearly polarized light interactions include the photoinduced magnetic anisotropy effect and the inverse Cotton–Mouton effect, which exist mainly in the insulating magnetic oxides where the optically stimulated magnetization dynamics changes its phase or magnitude upon tuning the pump polarization direction.The circularly‐polarized light excitation can cause the inverse Faraday effect related to the impulsive stimulated Raman magnetic scattering independent of photon absorption,6, 7 it is remained to be demonstrated how to coherently control magnetization in the FM metals using the linearly polarized light. To this end, we propose to adopt a strategy of ultrafast nonthermal control of magnetization in FM metal Co coupled with the ferroelectric (FE) material BiFeO3 by taking into account the advantages of pronounced optical rectification effect (ORE) and ferroelastic response in BiFeO3. When the FE is under intense illumination, the second‐order optical response combined with a linear term is well known to induce an extra FE polarization, and this FE polarization can consequently generate electrostriction in the system to modulate the magnetic energy of Co, depending on the light polarization direction.Although the circular‐polarized femtosecond laser pulses can be used to nonthermally excite and coherently control the spin dynamics in FM metals via the inverse Faraday effect,22 it 3 crystals. It was also found that the BiFeO3 crystal exhibits a pronounced photostriction effect under linearly polarized light illumination, and its elongation critically relies on the polarization direction. In this case, the photostriction effect can be understood as the superposition of photovoltaic and converse piezoelectric effects. Recently, it was further demonstrated that the strain characteristics of the FE BiFeO3 impinged by the photostriction effect can modulate magnetic anisotropy of the adjacent FM Ni layer in a Ni/BiFeO3 heterostructure. This result confirms the scientific feasibility of the FM‐FE coupling system using the optical modulation scenario. However, until now, the magnetic dynamics response in FM‐FE systems by the light‐induced photostriction effect has been elusive.Actually, the photovoltaic response, induced by the ORE, depending on the light polarization direction was already observed in bulk rhombohedral FE BiFeOcrystals.23 It 3 by using linearly polarized femtosecond laser excitation. We utilized the time‐resolved magneto‐optical Kerr effect (TRMOKE) to monitor the excited spin precession in the FM Co layer coupled with the FE BiFeO3 for different pump laser polarizations. It was found that the amplitude of magnetization precession with the linear polarization (βE) of pump laser pulse follows a sinusoidal profile with a periodicity of 180o. In contrast, the magnetization precession amplitude in the pure Co film has no such angular dependence. We also measured the ultrafast laser‐induced dynamics of the single BiFeO3 film and thereby obtained its light‐induced transient FE polarization. Actually, these FE polarization‐related signals also appear in the Co/BiFeO3 bilayer, and they both display a sinusoidal dependence on βE, which is in agreement with the deduction from the ORE. We thus believe that the nonthermal optical control of the magnetization precession in Co/BiFeO3 originates from the FE layer BiFeO3 due to its photostriction effect.In this paper, we have demonstrated the ultrafast nonthermal control of the magnetization precession dynamics in Co/BiFeO22.1Figure 3 heterostructure, the ORE in BiFeO3 first leads to the direct current (dc) polarization that depends on both the polarization of pump light and its spontaneous FE polarization, and the subsequent electrostriction effect causes the strain in the bilayer. This strain modulates the magnetic anisotropy in the Co layer, resulting in the various modulation of its magnetization precession for the different light polarization. Such scenario describes a linear polarization‐dependent magnetization precession excitation in FM metals, which may represent a promising route for ultrafast nonthermal control of magnetization in conventional FM materials.As illustrated in 2.23 bilayer used in this study was grown on (001) oriented Nb‐doped single crystal SrTiO3 (STO) substrate . From the XRD measurements, the BiFeO3 has a tetragonal‐like single crystalline structure . The probe laser pulses of 800 nm with p‐polarization are incident at a 45° oblique angle and undergo the transient polarization rotation (θK) upon reflecting from the sample. A vector magnetic field is within the sample surface along a certain direction (θH). The sample surface is placed in the vertical x‐‐y plane and the surface normal parallel along [001] is defined as the z axis. The TRMOKE system was also used to measure the θK related to the pump pulse induced transient FE polarization and the resultant strain in the Co/BiFeO3 bilayer and the pure BiFeO3 film. Detailed TRMOKE experimental information can be found in the Experimental Section.The Co/BiFeO2.33, we measured the magnetization dynamics excited by an s‐polarized pump laser for different magnetic field orientations (θH) and strength to obtain the field impact on the magnetization precession excitation. From Figure θK signals, corresponding to the uniform spin precessions excited in Co, strongly depend on θH. The precession amplitudes display a large variation with θH, and the precession phases switch 180° for varying θH. With increasing field strength, the precession amplitudes first increase and then decrease, whereas the precession phases keep unchanged, even for opposite θH  + H2cos(2θM) and Hβ = 4sπM + H4[2 − cos2(2θM)]/2 − H2sin2(θM), and γ is the gyromagnetic ratio (1.8 × 107 Hz/Oe for Co), θM denotes the orientation angle of the magnetization in the Co layer with respect to the x axis. MS represents the saturated magnetization, and H2 = 20 Oe and H4 = 40 Oe denotes the two and four‐fold anisotropy fields, respectively.The measured precession frequency with θH = 45o actually coincides with the direction of the external field applied along the [110] of the BiFeO3 layer during the sputtering of the Co layer. This indicates the importance of the in situ magnetic field during the growth for forming the cubic magnetic anisotropy in the Co layer, although it is not in a perfect single crystalline structure because of the lattice mismatch between the two layers. The emergence of the uniaxial magnetic anisotropy is likely due to the presence of a net spontaneous FE polarization in BiFeO3 along the y//[010] direction. This FE polarization component yields a strain along the [010] axis to make it as the uniaxial hard axis. Such in‐plane FE polarization was actually observed in BiFeO3 films with tetragonal‐like structures.The cubic magnetic easy axis along 2.4βE) dependent measurements were then performed at θH = 120o and H = 1.5 kOe. Figure βE, from which we can see an apparent difference in precession amplitude. Here, we should emphasize the constant pump fluence when rotating the half‐wave plate to tune βE. To get a deep insight into the relationship of the amplitude with βE, we fitted each θK(t) curve with the function ofA, f, φ, and τ represent the amplitude, frequency, initial phase, and lifetime of the precession, respectively. B denotes the long‐lived dc signal.The linear pump polarization βE dependeβE in the range of 360o. It clearly displays a sinusoidal oscillation with a period of 180o. The amplitude extrema appears for s or p‐polarized pump light. In addition, we note that the long‐lived dc signal (B) also has a sinusoidal variation with the same period of 180o, but it exhibits a phase difference of 45° compared to the precession amplitude variation  on Nb(001)SrTiO3 for different βE. Roughly, the θK signals show a fast rising within 1 ps and then a fast decay at the time scale of 10 ps followed by a very slow decay of several hundred ps  at ≈0.2 ps . These small peak II signals are not present in Co/BiFeO3 is possibly due to the much weaker third‐order nonlinear optical response, because of the attenuation of light by the Co layer and the obscuration by the ultrafast demagnetization signals.In addition to this peak (peak I) at ≈0.5 ps, we note in the pure BiFeOs Figure , which ps Figure . The pea3 can stimulate a new macroscopic electric polarization described as follows:ε0 is the vacuum dielectric constant, χ(3) and χ(2) are the fourth‐ and third‐ susceptibility tensors of BiFeO3, respectively, Eω(t) and Eω∗(t) denote the laser fields, P denotes the spontaneous FE polarization, and P0(2) represents the direct current term of light‐induced polarization, in accordance with the ORE, while P2ω(2)(t) represents the contribution to the second harmonic generation.An intensive laser pulse propagating in the FE BiFeO follows:39 due to the ORE. In the case of an in‐plane spontaneous polarization vector Py, P0(2) is expressed as:βE in the form of cos2βE or sin2βE. A similar result can be obtained for the case of Px. Whereas for the spontaneous polarization vector Pz, the in‐plane P0(2) component is zero and the out‐of‐plane P0(2) has no dependence of βE.According to the tetragonal crystal symmetry of BiFeOs Figure , we can βE with the period of 180o in the presence of an in‐plane spontaneous FE polarization, in line with the corresponding θK peak values shown in Figures s‐polarized probe light, yielding the θK signals. From Equations βE=45o and 135o. Such βE values thus should correspond to the largest modulation of the probe light polarization, which actually explains the observed θK extrema at βE=45o and 135o. For the pure BiFeO3 film, the θK signals are all positive is likely due to the superposition of the contribution from the modulated spontaneous polarization independent of βE. Whereas for the Co/BiFeO3 bilayer, the ultrafast demagnetization signal from Co is further superimposed, thus affecting the sign of θK signals.The above calculations show that the ORE‐induced FE polarization has a sinusoidal dependence on 3 causes the strain in the bilayer system. This strain modulates the magnetic anisotropy in the Co layer and provides an extra magnetic torque, in addition to the demagnetization related torque as a result of the heating effect, to drive the magnetization rotation followed by the periodic precession after the torque is nearly vanished. However, in contrast to the FE polarization induced θK, the largest precession amplitude must appear when the magnetic energy difference between the local easy axis along 135o and the hard axis along 90o has the strongest modulation. This is because the magnetization is in a canted geometry as a consequence of the noncollinear alignment of the magnetic anisotropy fields and applied field when the latter is along θH = 120o, and the strongest magnetic torque resulting in the largest precession amplitude is generated when the anisotropy fields undergo the strongest modulation. As mentioned above in the Section 3 owing to the strain along the [010] axis caused by the spontaneous FE polarization. From Equation βE=0o or 90o. As a consequence, the uniaxial magnetic anisotropy may be modulated at the largest scale and the precession amplitude presents extrema at these βE values, as shown in Figure θK peak with βE exhibit 45o phase shift.As described at the beginning of the results section, in the presence of light‐induced FE polarization, the electrostriction effect in the BiFeOβE. Actually, it was found in BiFeO3 film that the ORE‐induced strain affects the coherent acoustic phonons mainly within 50 ps. Nevertheless, we still observe a small long‐lived dc signal with the sinusoidal variation with βE, presenting opposite phase with that of the peak θK signal, as shown in Figures θK as compared to that induced by the transient FE polarization. Furthermore, based on the overall shape and phase correlation between the βE dependences of precession relaxation time τ and the transient FE polarization and long‐lived dc signals, we infer that the damping of magnetization precession is affected by the residual strain proportional to the transient FE polarization.Although the modulated FE polarization plays an important role in generating the strain‐related transient anisotropy fields to trigger the magnetization precessions, it greatly attenuates within a few picoseconds as shown in Figure  We believe that the relatively smaller nonthermal origin stems from the weak magnetic anisotropy relevant to the FE polarization as a result of the nonperfect single crystalline structure of the Co film and the existence of multidomain FE state in BiFeO3. We anticipate that the nonthermal modulation of the magnetization dynamics can be greatly enlarged in samples with the improved crystallinity and single domain structure of large in‐plane FE polarization. Actually, the helicity‐dependent magnetization modulation is much weaker compared to the heat‐driven demagnetization in the pure metallic ferromagnet under laser excitation. The deterministic magnetization reversal due to the inverse Faraday effect reported in reference  axis of BiFeO3. The metal Ta was chosen as the top protective layer with a thickness of 1.5 nm.To prepare the Co/BiFeOβE). The pump fluence on the sample was kept constant at ≈0.5 mJ cm−2. The probe laser pulses of 800 nm were incident at a 45° oblique angle, and the transient polarization rotation (θK) of the reflected probe pulses was detected by a balanced detector in the combination of a half‐wave retarder and a Wollaston prism. In the TRMOKE measurements, a vector magnetic field was applied within the sample plane along a certain direction (θH) to align the magnetization of Co to the desired orientation (θM).In the TRMOKE system, a Ti: Sapphire laser amplifier delivers laser pulses with the pulse width of ≈100 fs, the laser repetition rate of 1 kHz, and central wavelength of 800 nm. The 400 nm laser pulses, used as the pump light incident perpendicularly on the sample, were generated by frequency doubling the 800 nm pulses in a beta barium borate (BBO) crystal. Before incidence on the sample, the pump laser transmitted a polarizer followed by a zero‐order half‐wave plate to tune its polarization angle (The authors declare no conflict of interest.Supporting InformationClick here for additional data file.