But whether D(A‐a)O2 impacts the prognosis of patients with sepsis remains to be explored. Our study aims to investigate the association between D(A‐a)O2 and 28‐day mortality in patients with sepsis using a large sample, multicenter Medical Information Mart for Intensive Care (MIMIC)‐IV database.Lung is often implicated in sepsis, resulting in acute respiratory distress syndrome (ARDS). The alveolar–arterial oxygen gradient [D(A‐a)O2 on 28‐day death risk was investigated, with D(A‐a)O2 as being the exposure variable and 28‐day fatality being the outcome variable. Binary logistic regression and a two‐piecewise linear model were employed to explore the relationship between D(A‐a)O2 and the 28‐day death risk after confounding factors were optimized including demographic indicators, Charlson comorbidity index (CCI), Sequential Organ Failure Assessment (SOFA) score, drug administration, and vital signs.We extracted a data of 35 010 patients with sepsis from the retrospective cohort MIMIC‐IV database, by which the independent effects of D(A‐a)O2 was linked with a 3% increase in the probability of death at 28 days either in the unadjusted model or in adjustment for demographic variables . But, each 10 mmHg increase in D(A‐a)O2 was associated with a 3% increase of death  in the case of adjustment for all covariants. Through smoothed curve fitting and generalized summation models, we found that non‐linear relationship existed between D(A‐a)O2 and the death at 28‐day, which demonstrated that D(A‐a)O2 had no any impacts on the prognosis of patients with sepsis when D(A‐a)O2 was less than or equal to 300 mmHg, but once D(A‐a)O2 exceeded 300 mmHg, however, every 10 mmHg elevation of D(A‐a)O2 is accompanied by a 5% increase of the 28‐day death .A total of 18 933 patients were finally included in our analysis. The patients' average age was 66.67 ± 16.01 years, and the mortality at 28 days was 19.23% (3640/18933). Multivariate analysis demonstrated that each 10‐mmHg rise of D(A‐a)O2 is a valuable indicator for the management of sepsis patient, and it is recommended that D(A‐a)O2 be maintained less than 300 mmHg as far as possible during sepsis process.Our findings suggests that D(A‐a)O 2 is a valuable indicator for the management of sepsis patient. When D(A‐a)O2 was less than or equal to 300 mmHg, it has no any association with the prognosis of patient, but the mortality rate increases once D(A‐a)O2 became greater than 300 mmHg. The safe range of D(A‐a)O2 for patients with sepsis in the hospital and ICU is less than 300 mmHg.D(A‐a)O The disease has been paid more and more attention to by clinicians since 1991, and Surviving Sepsis Campaign (SSC) guideline has been updated several times since its first version in 2001,2) is a specific indicator reflecting the diffusion capacity of lung function, with a normal physiologic range of 7–14 mmHg2] being 21%), which is also associated with age. The capacity has been proven to be impaired in some conditions such as severe pulmonary, especially in acute respiratory distress syndrome (ARDS). Clinical studies reported that D(A‐a)O2 could identify COVID‐19 patients at risk of developing severe pneumonia early2 could predict the short‐term prognosis in patients with submassive pulmonary embolism and is useful in risk stratification of these patients.2 value increase), resulting in oxygenation dysfunction, a pivotal mechanism for sepsis genesis.2 may be linked to sepsis prognosis.The alveolar–arterial oxygen gradient ‐IV large sample sepsis database from the United States. A larger sample size would provide more consistent and trustworthy results, enabling us to gain a better understanding of the relationship between these two variables in sepsis.The goal of our study is to investigate the relationship between D(A‐a)O22.1The data was sourced from the MIMIC‐IV database, which was designed to be applied in retrospective cohort research, including clinical data of patients treated at Beth Israel Deaconess Medical Center (BIDMC) from 2008 to 2019. The database is free to be downloaded once one completes an approved course on the official website. Lu Chen, one of our authors, has finished the certified course and acquired access to the database, and she hence is in charge of data extraction (record ID: 50668217). Our analysis conforms to the RECORD  statement.2.22 value, with 28‐day death as the outcome variable  and the D(A‐a)O2 value as the exposure variable (recorded as a continuous variable). The worst D(A‐a)O2 values from the first day of ICU admission were extracted for analysis. Patients with missing exposure variable information were not included in this study.The MIMIC‐IV database includes 377 207 adult patient records in total, from which we extracted data of 35 010 ones with sepsis diagnosis. The extraction was based on the ICD‐9 and ICD‐10 codes recorded in the database , spanning from 2008 to 2019. All of these patients whose data were extracted received treatment at BIDMC. We examined the interaction between 28‐day death and D(A‐a)O2/FiO2 value, heart rate and body temperature at admission; use of mechanical ventilation, glucocorticoids , vasoactive drugs , immunoglobulins, and antibiotic administration .Based on our clinical experience and the literature,2.3The MIMIC‐IV database was authorized by the institutional review boards of BIDMC (2001‐P‐001699/14) in Boston, Massachusetts, and the Massachusetts Institute of Technology (0403000206). It is now available on the internet. Patient's informed permission was revoked as the data is publicly available, and the patient's identifiable information is uncertain.2.4Multiple interpolation was not utilized to fill in the blanks as the missing rate of the variables used in this study was less than 5% (0–4.1%).2.52 and 28‐day mortality under four different models, that is, Model 1 (no factors were adjusted), Model 2 (adjusted for demographic characteristics only) and Model 3  and calculated P for the trend of relationship. The purpose of sensitivity analysis was to determine whether the results of categorical variable were as robust as those of the continuous variable. (2) We employed several different adjustment strategies to evaluate the robustness of our results.Continuous variables were expressed as the mean + standard deviation (Gaussian distribution) or as the median  (skewed distribution). Categorical variables were presented as rate (percentage). Considering that it was a cohort study, we categorized exposure variables into four groups  and examined the distribution of patient baseline information across the different subgroups. To evaluate any statistical differences between the means and proportions of the groups, we performed one‐way ANOVA (Gaussian distribution), Kruskal–Wallis H (skewed distribution), and chi‐square tests . Meanwhile, we also employed univariable and multivariable binary logistic regression models to investigate the relationship between D(A‐a)O2 is a continuous variable, it could not be excluded that a nonlinear association existed between D(A‐a)O2 and 28‐day mortality. Therefore, we performed the generalized additive models (GAM) and smoothed curve fitting to investigate the connection between D(A‐a)O2 and sepsis 28‐day mortality. If the nonlinear relationship dose exist, we will explore the inflection point value by using a recursive technique then utilize the two‐piecewise linear model to obtain the OR value and 95% confidence interval on both sides of the inflection point.As D(A‐a)Ohttp://www.r-project.org, The R Foundation) and EmpowerStats . P value of less than 0.05 (two‐sided) is considered to be statistically significant.All analyses were carried out with the statistical programs R (33.12 information and another 290 are with D(A‐a)O2 value of less than 0. Ultimately, the data of 18 933 patients were included for the final analysis. O3.22 as categorical variable and 28‐day mortality, we categorized D(A‐a)O2 into four groups (Q1 to Q4) (Table In order to observe the association between D(A‐a)O groups Q to Q4 O2 was linked with a 3% increase in the probability of death at 28 days either in the unadjusted model or adjusted for variables in model 2 (Odds ratio (OR): 1.03, 95% CI: 1.02 to 1.03). In the adjustment of variables in Table 2 was accompanied with 3% of 28‐day mortality elevation . In order to observe the trend testing, we conducted a sensitivity analysis, in which we converted D(A‐a)O2 into a categorical variable (quartile). The results demonstrated that when D(A‐a)O2 was treated as a categorical variable, the results were consistent with when D(A‐a)O2 was used as a continuous variable O3.42 and 28‐day death. After adjusting for all covariables shown in Table 2 and 28‐day mortality, which demonstrated that D(A‐a)O2 had no impacts on 28‐day mortality when D(A‐a)O2 was less than or equal to 300 mmHg; but, once D(A‐a)O2 value exceeded 300 mmHg, every 10 mmHg elevation of D(A‐a)O2 was associated with a 5% increase of mortality  O42 and 28‐day mortality in patients with sepsis, with an inflection point of 300 mmHg of D(A‐a)O2, which demonstrated that when D(A‐a)O2 was less than or equal to 300 mmHg, it has no association with the prognosis of the patient, but once D(A‐a)O2 became greater than 300 mmHg, each 10 mmHg increase is associated with a 5% increased risk of mortality . As far as we know, few previous clinical studies have focused on the relationship between D(A‐a)O2 and the prognosis of sepsis patient.In this large retrospective cohort analysis, we discovered a curvilinear association between D(A‐a)O2 refers to the difference between the alveolar and the arterial oxygen partial pressure, with the capability of hypoxia detection, which is mainly associated with pulmonary diffusion function, anatomical shunt, and so forth. In physiologic condition, D(A‐a)O2 will increase with the rise of concentration of inhaled oxygen, but rarely exceeds 56 mmHg.2 dramatically elevated, such as interstitial pneumonia, sever pulmonary fibrosis, and ARDS, in which diffusion dysfunction or ventilation/perfusion (V/Q) ratio mismatch occurred. D(A‐a)O2 is therefore often used as an indicator to measure the severity of these diseases. For patients with submassive pulmonary embolism, Ince O et al found that a D(A‐a)O2 of ≥42.38 mmHg had a good predictive value for a 90‐day mortality, with an area under curve of 0.83 and a sensitivity, specificity, and negative predictive value of 93.3%, 65.1%, and 98.6%, respectively.2 is superior to PaO2/FiO2 in identifying COVID‐19 patients at risk of developing severe pneumonia early, with an area under curve of 0.877 and a sensibility of 77.8%, a positive and negative predictive value of 75% and 94%, respectively, in the case of D(A‐a)O2 being ≥60 mmHg.2 was significantly higher in this population than in previous studies. In Pipitone et al's study, D(A‐a)O2 was obtained on admission to hospital. However, the study population was COVID‐19 patients, and the outcome was whether or not they had severe pneumonia. Therefore, the patients had D(A‐a)O2 measured on admission, and their lung function did not deteriorate at that time. This suggests that the specimens were likely collected and analyzed for blood gas in a situation where mechanical ventilation was not being used.D(A‐a)O2 and 28‐day death of patient with sepsis by using univariate and multivariate analyses, in which D(A‐a)O2 was used as an exposure variable and 28‐day death as an outcome variable with other variables being adjusted. We found that 28‐day mortality climbed with the increase of D(A‐a)O2 whether D(A‐a)O2 was used as a continuous or a categorical variable. We further conducted smoothed curve fitting by adjusting all other covariables and found out a nonlinear association between D(A‐a)O2 and the risk of 28‐day death in sepsis patient, in which a 5% increased risk of death was paired with a 10 mmHg rise of D(A‐a)O2 when D(A‐a)O2 was more than 300 mmHg. As we employed multiple statistical analyses and adjusted all other cofounders, we think our results are reliable.In our retrospective analysis, we first observed the relationship between D(A‐a)O2 values of many patients were more than 300 mmHg, a value obviously exceeding the normal threshold, implying many sepsis‐induced ARDS patients in our analysis. Therefore, we have the reason to think that patients with D(A‐a)O2 of more than 300 mmHg are actually these patients with diffusion dysfunction and/or V/Q mismatch, that is, sepsis‐induced ARDS. So the nonlinear relationship found in our result means that the more serious the sepsis‐induced ARDS, the higher the possibility of 28‐day death. Anyway, our reliable findings suggested that D(A‐a)O2 values are useful indicators effectively predicting the risk of 28‐day death in patients with sepsis.Sepsis begins with an infection and progresses to multiple organ dysfunction via cytokine storm, among which respiratory system is vulnerably involved, mostly represented as a sepsis‐induced ARDS. Clinical data demonstrated that once sepsis patients was complicated with ARDS, their condition would inevitably deteriorate and their survival probability would also significantly be affected.2 and death.(3) The more covariate data, together with the presentation of multiple adjustment strategies and sensitivity analyses, ensure the robustness of the results and decrease the probability of chancing conclusions.Our work has the following advantages: (1) It has a large sample size and statistically significant power; (2) It employs a generalized summation model and a two‐piecewise linear model, both of which are advanced algorithms used to better determine the genuine association between D(A‐a)OMeanwhile, there are some limitations in our analysis: (1) Given that this is a clinical retrospective study, it is inevitably subject to confounding factors. Nevertheless, we have systematically accounted for the confounding factors, and the robustness of the results has been examined by sensitivity analysis. (2) Due to the nature of observational studies, we can only observe relationships rather than determine cause and effect. (3) We can only account for detectable confounding, not unmeasurable puzzling, so extensive clinical research with stronger levels of evidence in larger populations is required to corroborate our findings. (4) As the population investigated in this study involves septic patients in the United States, researchers will have to exercise caution when extrapolating our findings to other populations. (5) Given that this study is a secondary data analysis based on a large, multicenter critical care database, we were unable to include patients based on definitions and clear criteria for sepsis and septic shock as in the actual clinical scenario. This could potentially result in some patients who meet the definition of sepsis or diagnostic criteria not being included. However, because it is not possible to determine whether this misclassification is related to the exposure variable as well as the outcome variable, the impact of this misclassification on our findings is unknown.52 has a nonlinear impacts on the risk of 28‐day death in patients with sepsis, meaning, the D(A‐a)O2 is a reliable indicator to predict the prognosis in this population.Our results demonstrated that D(A‐a)OYing Wang contributed to study concept and design and drafting of the manuscript. Lu Chen gained access to the database and is responsible of the data extraction. Yan He interpreted the data. Ying Liu, Jia Yuan, Hongying Bi, Qimin Chen, and Xianjun Chen helped with the data arrangement. Feng Shen contributed to the study concept, supervision and organized the final manuscript. All authors have read and approved the manuscript for publication.The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.The study has been approved by the Ethics Committee of Affiliated Hospital of Guizhou Medical University in accordance with the Helsinki Declaration.All authors consent to publicize the manuscript in the Internal Medicine Journal.2D(A‐a) Oalveolar–arterial oxygen gradientARDSacute respiratory distress syndromeSOFASequential Organ Failure AssessmentTable S1: Adjustment vs no adjustment for Dopamine, Dexamethasone, Methylprednisolone, and Immunoglobulins use in logistic regressionTable S2: Adjustment vs no adjustment for Norepinephrine use in logistic regressionTable S3: Adjustment vs no adjustment for vancomycin, carbapenems, and cephalosporin use in logistic regressionClick here for additional data file.


This paper investigates the use of lithium (Li) ions as dopant for Sb2Se3 films, using lithium hydroxide (LiOH) as a dopant medium. Surprisingly, the LiOH solution not only reacts at the back surface of the Sb2Se3 film but also penetrate inside the film along the (Sb4Se6)n molecular chain. First, the Li ions modify the grain boundary's carrier type and create an electric field between p‐type grain interiors and n‐type grain boundary. Second, a gradient band structure is formed along the vertical direction with the diffusion of Li ions. Third, carrier collection and transport are improved at the surface between Sb2Se3 and the Au layer due to the reaction between the film and alkaline solution. Additionally, the diffusion of Li ions increases the crystallinity, orientation, surface evenness, and optical electricity. Ultimately, the efficiency of Sb2Se3 solar cells is improved to 7.57% due to the enhanced carrier extraction, transport, and collection, as well as the reduction of carrier recombination and deep defect density. This efficiency is also a record for CdS/Sb2Se3 solar cells fabricated by rapid thermal evaporation.The efficiency of antimony selenide  of the device by optimizing the back contact, decreasing deep‐level defects, and forming a gradient band structure.Surprisingly, the lithium hydroxide solution, which is also used for corroding the Sb Other desirable optoelectronic characteristics of Sb2Se3 film include a sufficient bandgap (1.03 eV) and a high absorption coefficient (>10−1). These materials are made up of plentiful, non‐toxic, and inexpensive component elements. In recent years, there has been significant progress in increasing the efficiency of Sb2Se3 thin‐film solar cells.2Se3 solar cells is 10.57% for an superstrate structure, in which the Sb2Se3 film was prepared using the chemical bath deposition (CBD),2Se3 film was prepared using the injection vapor deposition (IVD) method.2Se3 solar cells.Antimony selenide  films. However, the fermi level pinning effect caused by deep‐level defects in Sb2Se3 film hinders effective band structure adjustment through doping, leading to insignificant improvement in the efficiency of Sb2Se3 solar cells. Therefore, effective methods to modify the band alignment at the Sb2Se3/CdS interface are urgently needed to increase the open circuit voltage (VOC) of Sb2Se3 solar cells further.2Se3 film and high work function Au electrode, thus, restricting the efficiency increase of Sb2Se3 solar cells.2S3, Sb2Se3, and Sb23 solar cells. However, the Li‐TFSI used in Spiro‐OMeTAD is prone to deliquescence in the air, and the toxicity of 4‐tert‐butylpyridine and chlorobenzene poses a potential safety hazard. Although many inorganic films have been used as the hole transport layer to increase the efficiency of Sb2Se3 solar cells, the efficiency is still far below the recording device that used Spiro‐OMeTAD as the hole transport layer. Therefore, identifying a more suitable hole transport layer or reaction etching at the back surface is crucial for the future development of Sb2Se3 solar cells. To address these issues, this paper proposes using small atomic diameter lithium (Li) ions as dopants to dope the Sb2Se3 film, with lithium hydroxide (LiOH) acting as the dopant medium. Doping with Li ions can simultaneously solve the above three problems. Li‐ion doping can invert the carrier type of the grain boundary to decrease the deep defect density. With the diffusion of Li ions and the reaction at the back surface, the device's carrier transport and collection are increased.The efficiency of Sbficiency.13 Ano2Se3 film, with LiOH acting as the dopant medium. We hypothesized that Li ions could easily enter the large gap between (Sb4Se6)n ribbons, invert the carrier type of the grain boundary, and obtain a built‐in electric field from grain interiors (p‐type) to grain boundary (n‐type). During the LiOH and Sb2Se3 film reaction, Li ions could slightly enter the lattice of the Sb2Se3 film through Li ion diffusion. By varying the Li ions concentration, we could obtain Sb2Se3 films with a variable gradient band structure. The reaction between Sb2Se3 and LiOH solution increased the carrier collection and transport at the back contact surface. Furthermore, we extensively investigated the structure, crystallinity, orientation, and optical and electrical properties of Sb2Se3 film with a Li‐ion gradient. Finally, we achieved an efficiency of 7.57% for Sb2Se3 solar cells with a low deep‐level defect concentration.In this study, we used small atomic diameter Li ions as dopants to dope the Sb2Figure Figure 4Se6)n ribbons and subsequently enter the lattice due to the corrosivity of the LiOH solution. During the diffusion process, the Li‐ion concentration decreases as the diffusion depth increases, ultimately forming a gradient of Li ions within the Sb2Se3 film and resulting in the formation of the Li gradient field. Furthermore, the J‐V curves of the device with different concentrations of LiOH solution are shown in Figure m, the efficiency of the device increased significantly. However, with a sustained increase in concentration, especially above 0.1 m, the efficiency of Sb2Se3 solar cells decreased significantly. We believe that this phenomenon is caused by the corrosion damage of high‐concentration LiOH solution on the Sb2Se3 film. To validate our hypothesis and understand the impact of the Li gradient field on the Sb2Se3 film, detailed characterization was performed on the Sb2Se3 film and device.This study explores the formation of a Li gradient field through upper interface doping via a solution method. The detailed experiment process is shown in 2Se3 film, the researchers conducted a detailed analysis of the structure, crystallinity, electrical, and optical properties of the film with and without LiOH solution . Figure 2Se3 films. It is evident from the figure that all the peaks of both films correspond to orthorhombic Sb2Se3 (JCPDS#15–0861) with a preferred orientation along the [221] and [211] directions.2Se3 film is higher in the sample with a Li‐ion gradient.2Se3 film, the upper interface between Sb2Se3 film and Au electrode has been treated with different concentrations of LiOH solution. The detailed results are presented in Figure 2Se3 film was severely damaged as the concentration of LiOH solution increased, and at high concentration levels, the Sb2Se3 film was almost entirely corroded away. The XRD results of these six Sb2Se3 samples are displayed in Figure 2Se3 film, whereas high concentrations of alkaline solution can severely damage the structure of Sb2Se3 film.To investigate the influence of Li‐ion gradient on Sb2Se3 films with and without a Li gradient. The Sb 3d spectrum in Figure 3/2 and Sb 3d5/2 peaks are located at 538.6 and 531.1 eV, respectively, which are in agreement with literature reports.2Se3 film after adding LiOH solution. A prior study has demonstrated that an appropriate thickness of the Sb─O layer can reduce carrier recombination and enhance carrier transport in the device.2O3 is sustained increasing, the thick Sb2O3 may increase the current leakage, deep defect density and decrease the carrier collection at the back contact interface. The Se 3d peak is presented in Figure 3/2 and Se 3d5/2 peaks are located at 54.1 and 53.3 eV, respectively. Figure 2Se3 film with a Li‐ion gradient, where the peaks at 53.5 and 54.2 eV correspond to Li 1s, respectively.2Se3 film, and Li‐ion elements can enter into the Sb2Se3 film.Figure nterface.29 The2Se3 film, scanning electron microscopy (SEM) was performed on Sb2Se3 films with and without 0.01 m LiOH solution. As illustrated in Figure 2Se3 film without LiOH displayed a disorderly arrangement with numerous pin‐holes on the surface. However, the Sb2Se3 film with LiOH solution showed a flat and orderly surface with fewer pin‐holes, indicating that the LiOH solution had a corrosive effect. Figure 2Se3 films with and without LiOH solution, revealing that the Sb2Se3 film exhibited better crystallinity with larger grain sizes when LiOH solution was added. Atomic force microscopy (AFM) images of the Sb2Se3 films  were conducted on SbFigure2Se3 films with and without a Li gradient field. As shown in the figure, the resistivity and mobility of the Sb2Se3 film increased with the addition of Li gradient, whereas the hole carrier concentration decreased. Moreover, during the Hall test, the carrier type of the Sb2Se3 film with Li ions was always n‐type, which resulted mainly from the inversion of the carrier type at the grain boundary. In addition, the n‐type Sb2Se3 film has already been reported.EF) and valence band maximum  of the Sb2Se3 film. The conduction band minimum  was determined from the energy gap and VBM position. The energy levels of all samples were calculated from the UPS spectra and bandgap. The UPS results revealed that the distance between the EF and VBM was calculated to be 0.62 and 0.47 eV, respectively. With the addition of a Li gradient, the Fermi level moved toward the conduction band compared to its position in the film without a Li gradient. Additionally, the results demonstrated that the CBO between the Sb2Se3 film and CdS film was 0.5 eV, whereas with the addition of a Li gradient, the CBO between the Sb2Se3 and CdS films was 0.21 eV, which falls within the range of moderate spike‐like CBO values (0–0.4 eV).Figure 2Se3 films with different etching depths . In the band structure calculation process, it is challenging to estimate the band gap of the gradient Sb2Se3 film. Therefore, we hypothesized that the band gap of the Sb2Se3 film with different etching depths is consistent with the theoretical band gap. The EC for the sample with etching depths of 0, 150, 300, and 450 nm are −4.97, −4.4, −3.93, and −3.66 eV, respectively. These results support the steady enhancement of CBM structure in the Sb2Se3 films. Figure 2Se3 film with a Li gradient. Due to the gradient CBM structure, a large barrier is transformed into many small barriers, making it easier for carriers to cross over them. These relevant XPS and UPS results confirm the beneficial role of the gradient Sb2Se3 film in achieving high‐quality heterojunctions and efficient carrier transport.Figure J–V curves of Sb2Se3 solar cells with and without a Li gradient field. As shown in the figure, the addition of a Li gradient field has increased all of the device parameters, especially the Voc. The Sb2Se3 solar cells with LiOH solution achieved an efficiency of 7.57%, with a Voc, current density (Jsc), and fill factor (FF) of 0.41 V, 30.5 mA cm−2Se3 solar cells without LiOH solution obtained an efficiency of 5.2%, with a Voc, Jsc, and FF of 0.34 V, 28.66 mA cm−EQE) results of both devices. As seen in the figure, the device with a Li gradient field exhibited a high optical response in the long wavelength, indicating a reduction in the recombination rate and high carrier collection. Additionally, biased EQE measurements (defined as EQE (−0.5 V)/EQE(0 V)) were conducted on both devices. The results showed that the observed EQE ratio of Sb2Se3 solar cells with a Li gradient field was approximately unity during the entire spectrum. However, the observed EQE ratio of Sb2Se3 solar cells without a Li gradient field was strongly dependent on the bias, especially in the long‐wavelength region. The biased EQE results showed that the carrier collection of the device was optimized with the addition of a Li gradient field  and reverse saturation current density (J0) decreased significantly. The low ideal factor and reverse saturation current density can decrease carrier recombination and promote charge transport. Temperature‐dependent open circuit voltage measurements were conducted from 150 to 330K  and depletion region width (Wd) results are shown in Figure Vbi) of the device with and without treatment were 0.415 and 0.38 V, respectively. The improvement in Vbi can decrease the accumulation of photogenerated charge at the interfacial region, leading to an enhancement in the device VOC, as reported in previous studies. The depletion region width, which is used to analyze orientation‐related defects, was obtained from the C–V graph. For the Sb2Se3 film without and with Li gradient field, the depletion region widths were calculated to be 217 and 304 nm, respectively. A larger Wd value in the device with a Li gradient field could result in a greater collection of photogenerated carriers and contribute to a larger Jsc, as observed in the results of EQE.2Se3 film, non‐radiative recombination centers, specifically electrically active defects in Sb2Se3 solar cells with and without Li gradient field, were characterized using deep‐level transient spectroscopy (DLTS). DLTS is a technique that tracks the changes in the charge state of deep defect centers at various temperatures using the transient capacitance of the p‐n junction.To further examine the impact of the Li gradient field on the profound defects of Sb2Se3 layer were seen in the DLTS spectra for the Sb2Se3 solar cell with a Li gradient field, as shown in Figure 2Se3 solar cells without a Li gradient field, no negative peaks were observed, and three positive peaks  corresponding to minority‐carrier (hole) traps in the p‐type Sb2Se3 layer were observed. As shown in Figure Table Three negative peaks  corresponding to minority‐carrier (electron) traps in the p‐type Sb2Se3, resulting in slightly Se‐rich Sb2Se3 films. The previous study reported that under Se‐rich conditions, the dominant acceptor defects are antimony vacancy (VSb) and selenium antisite (SeSb) defects.Sb defect, while AD‐H2 and H3 are tentatively attributed to SeSb1 and SeSb2, respectively. Which is consistent to the previous theoretical work. As the location of Li‐GS‐H1 is close to the defect of AD‐H3, we suspect that the Li‐GS‐H1 defect is due to SeSb2. However, in the DLTS results with the addition of LiOH solution, three electrical traps appeared. We speculate that this phenomenon is due to two reasons. First, previous research has reported that the distribution of defects in trichalcogenides is dominated by antisite defects due to the similar sizes of the constituent atoms. Second, simulations have shown that SeSb and antimony antisite (SbSe) are acceptors and donor defects, respectively.Sb defect. Second, as the location of Li‐GS‐E1 and Li‐GS‐E2 is very close to the CBM, we believe that these two defects can be attributed to Li itself. Our hypothesis is that Li ions first accumulate on the surface of the Sb2Se3 film and then diffuse easily into the (Sb4Se6)n chains and lattice of the Sb2Se3 film due to the corrosive nature of LiOH solution and the large distance and small compactness at GBs. Microscale Li ions diffuse easily along the GBs and enter the gaps of the chains, resulting in n‐type Lii doping. This inversion creates a local electric field between GBs and GIs, facilitating spatial separation of photogenerated electrons and holes, thereby restraining carrier recombination and enhancing carrier collection, especially for carriers generated by red and infrared photons, resulting in improved efficiency. Additionally, it is worth noting that the defect density of the Sb2Se3 film with added LiOH solution decreased by order of magnitude. This reduction in defect density should decrease carrier recombination and increase carrier transport in the device.Figure cal work.43 As 32Se3 film to the alkaline solution, Li ions not only formed a back contact layer at the upper interface but also entered into the lattice of the Sb2Se3 film to enhance its crystallinity, optical, and electrical properties. The UPS results also indicated that with the addition of LiOH solution, a gradient band structure was formed inside the Sb2Se3 film, which should improve the carrier collection and transport of the device. The DLTS results also showed a reduction in defect density and grain boundary inversion which should suppress carrier recombination and enhance carrier collection, resulting in an improvement in PCE. Finally, an efficiency of 7.57% was achieved for Sb2Se3 solar cells. This is the highest efficiency reported for Sb2Se3/CdS solar cells based on rapid thermal evaporation. We believe that this work paves the way for further improvements in the efficiency of Sb2Se3 solar cells.In summary, the LiOH solution was used to modify the upper interface of the device. Due to the sensitivity of the Sb42Se3/Au. First, through single source evaporation , a 50 nm CdS film was evaporated onto the FTO substrate  using CdS powder . During the evaporation process, the substrate temperature was room temperature, the working pressure was 1.0×10−6 torr, the evaporation speed was 0.65 s−1, and the evaporation power was 35 W. The CdS film was then annealed in a tube furnace for one minute at 500 °C. Second, based on the RTE technique, Sb2Se3 films with a thickness of ≈500 nm were created in a tube furnace that was maintained at a pressure of 5 m Torr by a mechanical pump. The pre‐heating temperature was 310 °C for 20 min, and the depositing temperature was raised to 570 °C for 40 s. Third, the LiOH solution's concentration ranged from 0 to 0.1 m, with water serving as the solvent. Additionally, the Sb2Se3 films were heated at 100 °C while spin‐coating them with various LiOH concentrations for comparison. At last, Gold electrodes  was used to measure optical performance of all the Sb2Se3 films. UPS was carried out using a monochromatic He I light source (21.2 eV) and a VG Scienta R4000 analyser, while XPS was carried out using a Kratos Axis Ultra DLD system. For testing the electrical properties, Sb2Se3 films with different concentrations of LiOH were deposited directly on the glass substrate and measured using a Hall measurement system with van der Pauw configuration at room temperature and a magnetic flux density between 3000–5000G . The metal In was used as the electrode for the hall test. Deep analysis of the elements was performed with a TOF‐SMIS measurement system . The EQE of the solar cells was detected using a photovoltaic characteriszation system (PV Measurements QEXL), and the efficiency of the solar cells was measured using an I–V tester under AM 1.5G spectral irradiance with a radiance of 1000 W m−2. Using a Keysight Precision LCR metre (Keysight E4980AL) in complete darkness, at 25 °C, and at 10 kHz, the C–V was measured. A range of ‐1–0.5 V was used as the DC bias voltage. The DLTS spectra were obtained using the Phystech FT‐1230 HERA DLTS system, and temperature scans were made between 120 and 400 K, with 2K intervals.In this paper, the structure and crystallinities of all the SbThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The unclear structures and polydispersity of metal nanoparticles (NPs) seriously hamper the identification of the active sites and the construction of structure‐reactivity relationships. Fortunately, ligand‐protected metal nanoclusters (NCs) with atomically precise structures and monodispersity have become an ideal candidate for understanding the well‐defined correlations between structure and catalytic property at an atomic level. The programmable kernel structures of atomically precise metal NCs provide a fantastic chance to modulate their size, shape, atomic arrangement, and electron state by the precise modulating of the number, type, and location of metal atoms. Thus, the special focus of this review highlights the most recent process in tailoring the catalytic activity and selectivity over metal NCs by precisely controlling their kernel structures. This review is expected to shed light on the in‐depth understanding of metal NCs’ kernel structures and reactivity relationships. Compared to NPs, Ligand‐protected NCs with atomically precise structures and monodispersity have become an ideal candidate for understanding the well‐defined correlations between structure and catalytic property at an atomic level. Tuning the kernel structure of NCs to improve catalytic activity and selectivity by tailoring the number, types, and positions of metal atoms is a novel strategy. Nanocatalysis, which catalyzes by nanoparticles (NPs), catches everyone's eyes because it unifies the advantages of both homogeneous catalysis and heterogeneous catalysis. Compared to their counterparts, metal NPs have unique electronic structures, quantum‐size effects, rich active surface atoms, and a large surface‐to‐volume ratio, showing widespread applications in heterogeneous catalysis. Unfortunately, these metal NPs are not uniform at the atomic level, and thus include multiple active sites, showing the property of multiple reaction pathways and low selectivity for most of the catalytic processes. The polydispersity of NPs seriously affects the selectivity for desired products and hampers the identification of the active sites and reaction intermediates. Therefore, designing and synthesizing nanocatalysts with atomically precise structures is much needed.In the modern world, catalysis plays the most important role in science and industry because approximately 90% of the chemical processes and two‐thirds of the chemical products involve at least one catalytic process.4, 5 They have become a kind of star nanocatalysts for investigating the well‐defined relationships between structure and catalytic property. Metal NCs usually contain several to hundreds of metal atoms with core diameters ranging from 1 to 3 nm. These metal NCs show molecular‐like or non‐metallic behavior due to the quantized electronic structure arising from the quantum confinement effect, thus building a bridge between molecular catalysts and conventional metal NPs. With atomically precise structures in both the metal kernel and protected ligands, metal NCs are appropriate for the precise identification of active sites or reaction mechanisms by precisely modulating the core or surface structures while keeping other parts intact, which is difficult to achieve for metal NPs. So far, the regulation of the surface structure of metal NCs is usually related to ligand‐on, ligand‐off, and the type of ligands, whereas kernel structures of metal NCs have been successfully tailored by the precise regulation of the number, type, and position of metal atoms, offering a new strategy for exploring the structure‐reactivity relationships at the atomic level. For example, three thiolated‐protected Au25(SC6H13)18, Au38(SC6H13)24, and Au144(SC6H13)60 exhibited size‐dependent CO2 reduction reaction (CO2RR) activity with high CO selectivity (> 90%) and long‐term stability, which improved with increasing the number of Au. Jin and co‐workers reported the shape effects of NCs on catalysis. Au25 nanospheres showed a higher CO2RR performance toward CO formation than that Au25 nanorods. More interestingly, Zhu and co‐workers removed or doped one atom with the precise location in the atomically precise metal NCs to modulate the catalytic performance. Moreover, the mixed‐valence copper NCs [Cu54S13O6(tBuS)20(tBuSO3)12] (Cu54) supported on TiO2 exhibited excellent photocatalytic activity for phenol degradation under visible light. Therefore, these metal NCs provide an unprecedented opportunity to control catalytic performance and explore the catalytic mechanism of a catalyst by modulating the size, morphology, or even by an atom alteration.Metal nanoclusters (NCs) protected by organic ligands, possess atomically precise structures and molecular purity.26 TheThe focus of this review is to discuss and highlight the structure‐performance relationship between the kernel structure of atomically precise NCs and catalytic activity and selectivity, and summarize the factors that affect the kernel structure of atomically precise NCs, such as size, structural isomerism, doping, addition and removal of single atoms, charge effects, etc. Therefore, we can tune the kernel structure of NCs by adjusting the number, type, and location of metal atoms, which further improves the catalytic activity and selectivity of NCs in catalytic reactions. This review can provide insightful guidance for designing NC catalysts with enhanced catalytic performance and provide theoretical models for studying the intermediate states of NC catalysts in catalytic processes.2 In general, the overall electronic structure of atomically precise metal NCs is susceptible to slight changes in the size, shape, dopant, and charge of their metal cores, which in turn leads to different catalytic reactivity and selectivity. Here, we discuss the important role of programmable kernel structures in atomically precise metal NCs for tailoring catalytic activity and selectivity by regulating size, shape, doping hetero‐atoms, vacancies, structural isomerism, charge effects, etc.Compared with traditional nanocatalysts, atomically precise NCs can offer a better understanding of the catalytic mechanism at the atomic level.42 In 2.1n(SR)m NCs with different sizes provides an excellent chance to explore the size‐dependent catalytic activity at an unprecedented atomic level. As shown in Figure 333), transition NCs with a diameter of 2.3–1.7 nm (Au333 ∼ Au144), and nonmetallic NCs with a core size smaller than 1.7 nm (< Au144). They found that the Au NCs in the transition regime exhibited excellent catalytic activity in both CO oxidation and electrocatalytic alcohol oxidation compared with metallic and nonmetallic NCs. In addition, Au144 NC in the transition regime showed excellent catalytic performance and selectivity in both D‐glucose oxidation and methyl phenyl sulfide sulfoxidation, which was better than that of the metal NCs with a nonmetallic state. Tsukuda and co‐workers investigated a series of Aun NCs  with atomically regulated sizes on hydroxyapatite for the aerobic oxidation of cyclohexane. The turnover frequency (TOF) of these catalysts increased with increased size, reaching the highest value at n = 39 (TOF(Au39) = 18 500 h‒1 Au atom‒1), and thereafter decreased with a further increased size to n = 85.For a long time, it was a great challenge to explore the size‐dependent catalytic activity of NPs catalysts and the origin of this size dependence, due to the structural polydispersity and heterogeneity of the conventional NPs. The success in synthesizing a series of Au25(SC6H13)18, Au38(SC6H13)24, and Au144(SC6H13)60 NCs   calculations indicated that the dethiolated Au site showed a relatively high charge density and upshifts of d‐states, which promoted the CO2RR by stabilizing the *COOH intermediate m NCs 13, Au18(SG)14, Au25(SG)18, Au38(SG)24) and investigated their catalytic activity for the hydrogenation of 4‐nitrobenzaldehyde. All the Aun(SG)m catalysts exhibited ∼ 100% selectivity to 4‐nitrobenzyl alcohol, but their catalytic activity increased as their core size increased. DFT analysis revealed that the interaction between the ─CHO group of 4‐nitrobenzaldehyde and the Au(SR)2 staple motifs on the surface of Aun(SG)m leads to the difference in adsorption energies on different Aun(SG)m. Therefore, it can be concluded that the catalytic activity of these Au NCs is regulated by their surface area.Recently, Lee and co‐workers reported that Au) Figure  showed s8 > Au25.48 Bote Figure . Thus, t25 > Au38 > Au144) was reported by Jin and co‐workers for styrene oxidation. They discovered that the size‐dependent catalytic activity is closely bound up with the quantum confinement effects of these Au NCs. Another example with the same trend was reported by Chen and co‐workers. They used various Au NCs with different sizes, including Au11Cl3(PPh3)8, Au25(PET)18 (PET = SCH2CH2Ph), Au55(PPh3)12Cl6, and Au140(S(CH2)5CH3)53, for electrocatalytic oxygen reduction reaction (ORR) in alkaline conditions and found size dependence in which Au11Cl3(PPh3)8 with smallest core size exhibits highest ORR catalytic performance. Recent theoretical studies demonstrated that the smaller the core diameter of Au NCs, the narrower the d bands become. And the d bands would shift toward the Fermi level. Thus, the authors claimed that the smaller the core size of Au NCs, the stronger the adsorption capacity of O2, which may be responsible for the variation of the ORR catalytic performance in these Au NCs. Notably, the ORR limiting current density of the Au NCs also followed this order and all the values are much higher than Au NPs with diameters greater than 2 nm. Furthermore, the same group observed the same ORR trend for Au25(PET)18, Au38(PET)24, and Au144(PET)60, with Au25(PET)18 having the best ORR performance. Chakraborty and co‐workers also investigated the size‐dependent ORR performance of 4‐tert‐butlylbenzenethiol (TBBT)‐protected Au NCs from 1 to 2.2 nm. Unlike the results reported by Chen's group, as shown in Figure 28(TBBT)20 displays the highest overpotential of 540 mV to reach a specific current density and showed the worst selectivity due to the competition of the 2e‒ process. Although Au36(TBBT)24 has a similar core size to Au28(TBBT)20, it is the most effective ORR electrocatalyst as demonstrated by the minimum overpotential requirement (160 mV) and a complete 4e‒ pathway from O2 to H2O. Based on the overpotential, selectivity, and stability, the ORR performance decreases in the following sequence: Au36(TBBT)24 > Au133(TBBT)52 > Au279(TBBT)84 > Au28(TBBT)20. The more stable structure of Au36(TBBT)24 might be the main reason for the better ORR activity than Au28(TBBT)20 with a similar core size. Thus, the author indicated that even Au NCs with similar sizes can show striking distinction in catalytic performance just by changing a few Au atoms.An opposite trend in that smaller Au NCs exhibited higher catalytic activity 24‐Q and ‐T (Au38‐T/Q) were reported by Jin's group. As shown in Figure 38‐Q has a face‐fused bi‐icosahedral Au23 core, whereas the Au23 core of Au38‐T contains an icosahedra Au13 core and one Au12 cap via sharing two Au atoms. Furthermore, the surface structures of the two isomers are also quite different. Au38‐Q has three Au(SR)2 and six Au2(SR)3 staples to form the surface layer. The surface layer of Au38‐T contains three Au(SR)2, three Au2(SR)3, two Au3(SR)4 staple units as well as one bridging SR ligand. Interestingly, the two Au38 isomers exhibit different catalytic activities in reduction reactions. For instance, Au38‐T can reduce 4‐nitrophenol to 4‐aminophenol with a 44% yield, which is much higher than that of Au38‐Q (no reduction) under the same condition 24  NCs with different Au core arrangements but the same thiolate ligand. The intramolecular hydroamination of alkynes by Au36(DMBT)24 with a two‐dimensional (2D) arrangement of Au4 tetrahedral units (short for Au36‐II(DMBT)24) is better than that of Au36(DMBT)24 with a one‐dimensional (1D) arrangement of Au4 tetrahedral units (Au36‐I(DMBT)24). Experimental and computational studies demonstrated that the exposed Au sites of the two Au36(DMBT)24 catalysts favor distinct reaction intermediates and pathways. The exposed Au sites in the defective Au36‐II(DMBT)24 could indeed facilitate the hydroamination of 2‐ethylaniline by lowering the rate‐limiting activation barrier. While the defective Au36‐I(DMBT)24 binds to the exposed Au sites, which are vibrationally unstable and exhibit low catalytic activity. Two isostructural NCs (Ag25Cu4Cl6(dppb)6(PhC≡C)12(SO3CF3)3 and Ag25Cu4Cl6H8(dppb)6(PhC≡C)12(SO3CF3)3, abbreviated as Ag25Cu4 and Ag25Cu4H8, respectively, dppb = 1,4‐bis(diphenylphosphine)butane) were reported by Yuan et al. Compared with Ag25Cu4, the Ag25Cu4 kernel structure of Ag25Cu4H8 is distorted, and its Ag13 core is seriously expanded due to the participation of 8 hydrogen atoms. Moreover, Ag25Cu4 has 8 valence electrons and is generally considered to originate from the stable Ag13 core, so the metal atoms in the Cu4Ag12 shell should be in the +1 oxidation state. On the contrary, all metal atoms of Ag25Cu4H8 are +1 oxidation state. Ag25Cu4H8 reduced 4‐nitrophenol to 4‐aminophenol with up to 100% yield ascribed to the electron‐deficient Ag(I) and Cu(I) sites. While the conversion of Ag25Cu4 is only ∼ 8% under the same conditions due to the lower adsorption activity toward BH4‒.Zhang and co‐workers investigated the catalysis of two geometric isomers of Aue ligand.71 The28(S‐c‐C6H11)20 and Au28(TBBT)20 quasi‐isomers with the same Au20 kernel but completely different surface staple motifs. The different surface staple motifs of these two Au28 quasi‐isomers present different catalytic activities for CO oxidation. Liu et al. reported Cu8 clusters with one cube and two ditetrahedron‐shaped, exhibiting different catalytic performances of CO2RR. The results showed that the Cu8 cluster with ditetrahedron‐shaped exhibited higher activity and selectivity than the cube‐shaped Cu8 cluster at 1.0 V vs RHE (reversible hydrogen electrode) due to the lower free energy in the formation of the *COOH intermediate. This work provides a theoretical basis for atomically precise copper cluster models to elucidate the relationship between structure and catalytic performance, which lays the foundation for the study of copper‐based CO2RR electrocatalysts. Wang et al. reported a pair of Au28 (Au28(C2B10H11S)12(tht)4Cl4 and [Au28(C4B10H11)12(tht)8]3+ abbreviated as Au28‐S and Au28‐C, respectively, tht = tetrahydrothiophene) protected by carboranealkynyl and carboranethiolate. The *COOH structure adsorbed by CO2* hydrogenation of Au28‐S has a low ΔG value, so it exhibits an excellent electrocatalytic reduction of CO2 reduction to CO . Zhao et al. obtained two Au25 NCs of the same size but showed differences in atomic stacking 18 includes an icosahedral Au13 kernel and six Au2(SR)3 staple units, exhibiting a morphology of nanosphere. However, in Au25(PPh3)10(SR)5Cl2, two icosahedral Au13 kernels share one Au and are linked together via five bridging thiolates SR ligands at the waist part, forming a rod‐shaped morphology. Both two Au25 NCs are loaded on carbon black and applied as electrocatalysts for CO2RR. They found that the spherical Au25 NC exhibits higher current density and FE toward CO than those of the rod‐shaped Au25 NC at the whole range of applied potentials, indicating that the spherical Au25 NC processes better electrocatalytic activity for CO2RR than the rod‐shaped Au25 NC. The improved electrocatalytic performance can be attributed to the structural isomerism and negative charge state, which can stabilize the key *COOH intermediate of CO2RR  into Au NCs to tune their optical, electronic, and catalytic properties have been successfully achieved in many reports. Interestingly, because of the differences in electronegativity and size, each foreign metal may prefer a different place in the parent NCs. For example, Pt and Pd atoms are often replaced with the center atom of the Au25 NCs, exhibiting enhanced catalytic activities for styrene and alcohol oxidation. Although Cu and Ag atoms are located in the same group as Au, the Cu atom prefers to be doped at the icosahedral shell, whereas the Ag atom goes to the staple motifs. Here, we discuss the catalytic activity, selectivity, and stability of atomically precise alloy NC catalysts in the reaction system.Doping has become one of the most essential strategies for modulating the intrinsic physical/chemical properties of metal NPs.78 In 2.3.124(SC6H13)18, short as PtAu24) with excellent electrocatalytic activity and superior properties to commercial Pt/C catalysts in hydrogen evolution reaction (HER). Introducing a single Pt into the core can significantly alter the electronic structure of the parent Au25 NC and shift the reduction potential of PtAu24 NC positively by nearly 1 V in comparison with that of Au25 NC, which would lower the overpotential for reductive electrocatalysis. PtAu24 NC has a well‐matched reduction potential of HER and shows higher turnover frequencies (TOFs) of 4.8 molH2(mol cat)‒1 s‒1 in tetrahydrofuran and 34 molH2(mol cat)‒1 s‒1 in water at η = 0.6 V than any other HER catalysts under the same conditions. DFT results indicated that the energy change of the first step was thermodynamically neutral (−0.059 eV) for [PtAu24]2–, whereas it is + 0.539 eV for [Au25]–, indicating that the initial hydrogen binding is favored on [PtAu24]2− but is endothermic on [Au25]–, which can explain the superior HER performance for PtAu24 NC. It also should be pointed out that the bond distance between the doped Pt and the adsorbed H is 1.788 Å, which is much smaller than that of the surface Au and the adsorbed H (2.031 Å), implying the stronger binding affinity between H and Pt. This work further established that doping a single Pt atom into Au NCs can modulate the redox potentials and binding affinity, offering a great chance to investigate the structure‐property relationships by only changing one atom. Chen and co‐workers reported another single‐Pt–doped PtAu24 NC with superior electrocatalytic performance for direct formic acid oxidation (FAO), showing a closely 34 times higher mass activity than that of the commercial Pt/C catalyst. The excellent FAO catalytic performance of PtAu24 NC can be also ascribed to the regulation of the electronic structure via doping a single Pt atom.The introduction of single heteroatoms in alloy NCs offers a chance to investigate the mechanism of the reaction of catalytically active sites. Lee and co‐workers reported a single‐Pt–doped Au NCs (PtAuon (HER).91 Int24) as an electrocatalyst for CO2RR, showing a distinct doping effect compared to the parent Au25 NC . However, the CO FE of the parent Au25 NC started to decrease at −0.9 V and dropped to 60% at −1.2 V due to the increasing evolution of H2 at large currents. To the best of our knowledge, full ligand‐protected NCs have no exposed active sites due to the tight coat of the ligands. Therefore, removing a small part −SR ligands or cleaving the organic −R moieties by thermal or chemical treatment to expose metal active sites or S sites of NCs is an effective means to improve catalytic activity. As shown in Figure 2RR, whereas the Au sites are the active sites for H2 evolution. Doping a single Pd atom in the core of Au25 NC is beneficial for the retention of the S site in the ligand removal process under cathodic potentials, thus inhibiting H2 evolution at large currents. This work again demonstrated that the catalytic performances of Au NCs can be tailored by replacing only one foreign atom. In addition, a lot of works have investigated the doping effect of Au25 NC, indicating that Au25 NC gives a new insight into researching the structure‐property relationship by doping foreign atoms.Very recently, Jin and co‐workers successfully prepared a single‐Pd–doped Au NC  24(SR)18]q NCs 18]0‐O and partially ─SCH3 removed [HgAu24(SCH3)17]0‐O exhibited the best ORR activity to produce H2O2 and H2O among the single‐M–doped MAu24 NCs. From the Volcano relation as shown in Figure 25q and other doped MAu24q, the staple–doped Hg atom shows a strong s‐electron effect, rendering it an excellent ORR electrocatalyst. These results demonstrated that modulating the electronic structures of metal NCs tailors the catalytic activity by doping a metal atom. Except for Au25 NCs, single‐atom doping can be also achieved in other metal NCs. For example, an Au8Pd NC exhibited excellent catalytic performance for benzyl alcohol oxidation reported by Zhu and co‐workers, whereas Au9, Au24Pd, and Au25 NCs cannot. The authors concluded that the Pd site in Au8Pd NC served as the unique active site in the entire reaction system. The elegant work from the same group investigated single‐M–doped MAg24(SPhMe2)− NCs and further studied the center‐doping effect of catalytic capability in the carboxylation reaction of CO2. The foreign atoms indeed enhanced the catalytic performance, which follows as Au@Ag24 > Pd@Ag24 ≈ Pt@Ag24 > Ag@Ag24. The electron density on the Ag atoms decreased owing to the electron donation from the external Ag atoms to the foreign atoms, and the degree of the electron donation depended on the properties of the doped atoms. The enhanced catalytic performance was attributed to the more positive charge states of the MAu24 NCs with a higher chemical adsorption capacity of CO2. Furthermore, the central doping of foreign atoms into Ag25 NC can bring a significant enhancement in stability.In 2021, Tang and co‐workers presented a comprehensive investigation of single‐M–doped − (X = 24) loaded on a carbon black support and exhibited superior electrocatalytic performance for ORR in an alkaline environment compared to lightly doped Au clusters. The authors pointed out that one of the key factors influencing catalytic efficiency is the catalytic site. Yao and co‐workers quickly synthesized atomically monodisperse Au25Ag2 using the antigalvanic reduction method. The main structure of Au25 in Au25Ag2 is still maintained, while Ag2 is only incorporated into the surface of Au25. Compared with Au25, Au25‐xAgx can be kept for a week without change after exposure to air and light and also exhibited accelerated hydrolysis of 1,3‐diphenylpropyl‐2‐ynyl acetate with a conversion rate of 52% under the same conditions, which is mainly attributed to the two silver atoms on Au25 acting as active sites. This work provided insights into a better understanding of heteroatoms as active sites in nanoclusters.Jin and co‐workers successfully synthesized the heavily Ag–doped metal NC 2Cd(NO3)4 (abbreviated as Au26Cd5) exhibited superior catalytic performance and excellent recyclability for A3‐coupling reaction, whereas the Au25(PET)18 NC showed no catalytic activity for A3‐coupling reaction under the same conditions.26Cd5 is greatly affected by the synergy between the foreign Cd atoms and the adjacent Au atoms on the surface of the Au13 core. Meanwhile, NCs with rich electronic configurations due to the number of dopants have attracted extensive attention. Moreover, Liu and co‐workers reported an Au38Cd4(DMBT)30 bimetallic NC, which was synthesized by Cd‐induced surface recombination of Au44(DMBT)28 30 contains an FCC Au26 kernel which is slightly distorted from “slender” to “stout” compared to the kernel of the parent Au44(DMBT)28. While the two Au5Cd2(DMBT)12 staple motifs of Au38Cd4(DMBT)30 are formed by replacing four Au2(DMBT)3 stable motifs in Au44(DMBT)28 with two Au5Cd2(DMBT)12. As shown in Figure 44(DMBT)28, surface modification of Cd atoms in Au38Cd4(DMBT)30 causes an obvious change in the electronic structure. In particular, the Au38Cd4(DMBT)30 bimetallic NC exhibits better visible‐light‐driven catalytic decomposition of methyl orange compared to the parent Au44(DMBT)28 catalyst. This work offered a solid theoretical foundation for studying the electronic structure of NC to alter catalytic performance at the atomic level.Because Cd has one more valence electron than Au, the introduction of Cd usually results in the surface reconstruction of gold NCs and further modulates the physicochemical properties of NCs.33 Int8 Figure .103 Au4M2(SR)8, M = Ni, Pd, Pt; SR = SPhMe2; abbreviation as Ag4M2) with a distorted hexahedron structure composed of eight sulfur atoms as vertices. Four silver atoms are at the waist, and two heteroatoms are at the center of the top and bottom. The highest occupied molecular orbital and lowest unoccupied molecular orbital (LUMO) gaps of Ag4Ni2, Ag4Pd2, and Ag4Pt2 are 1.60, 2.24, and 2.61 eV, respectively, due to doping metal atoms. Therefore, the three Ag4M2 NCs have opposite photocatalytic degradation effects on methyl orange and rhodamine B, which was attributed to the difference in electronic structure.Cheng and co‐workers explored the catalytic performance of three metal–doped Ag clusters (Agvertices.104 Fo46Au24(SR)32](BPh4)2 , which was assembled by three layers of bimetallic Ag2@Au18@Ag20 kernel stabilized by doped Ag24Au6(SR)32 shell. In styrene oxidation, the styrene conversion of homogold Au25/CNT is 72.8%, which is higher than that of homosilver Ag44/CNT (43.6%). However, Ag44/CNT shows a much higher selectivity (92.6%) than Au25/CNT (66.4%) for benzaldehyde. Interestingly, surface–doped bimetallic Au24Ag46/CNT exhibits both better conversion ∼ 70% and higher selectivity > 95%, which can be attributed to the synergistic effect of gold and silver.The unique surface structures in alloy NCs provide a chance to study the structure‐activity relationship between structure and catalytic performance. Wang and co‐workers successfully synthesized the largest Ag‐Au alloy NC [Ag32 shell.105 In2Cu34(PET)22Cl4]2− (Pt2Cu34) by a metal exchange strategy using the [Cu32(PET)24Cl2H8]2− (Cu32) precursor. Pt2Cu34 contains an abnormally interpenetrating incomplete double icosahedral core (Pt2Cu18) bridged by a Cu16(PET)22Cl4 shell 11Cl and two Cu2PET motifs. Compared with Cu32, Pt2Cu34 has the loss of hydrides and retained 2‐electrons due to the introduction of large‐sized Pt atoms, while the total number of metal nuclei and free valence electrons also changed, increasing from 32 to 36 and from 0 to 10, respectively. The Pt atoms located in the core of NCs exhibit a doping‐induced synergistic effect that will facilitate the catalytic oxidation of silane to silanol . Lee and co‐workers synthesized Pt–doped copper NC + (Au24) and [Au25(PPh3)10(PET)5Cl2]2+ (Au25) to investigate the effect of only one Au atom on methane oxidation  can be converted into Au24 by reacting with excess triphenylphosphine. Therefore, Au24 and Au25 can be used as theoretical models to switch on/off the activity of NC catalysts by shuttling in/out only one atom.Removal or addition of central atoms can significantly tune the electronic structure of the NC catalysts and enhance or lose the catalytic activity for methane oxidation. Cai and co‐workers prepared two Au NCs  50 24 r Figure .[11011H3(Tf‐dpf)6(OAc)2 (Cu11) with three interstitial μ6‐H and Cu12H3(Tfdpf)6(OAc)2]·OAc (Cu12) with three interstitial μ5‐H, Tf‐dpf = N,N′‐Di(5‐trifluoromethyl‐2‐pyridyl)formamidinate). The core of Cu11 is composed of edge‐sharing rectangular pyramids that share two copper atoms. However, the core of Cu12 contains three face‐sharing octahedra, in which 12 copper atoms have a hexagonal close‐packed structure with ABAB stacking mode. Cu11 exhibits higher catalytic activity than Cu12 in the reduction of 4‐nitrophenol to 4‐aminophenol. The structure of copper hydride clusters and the coordination modes of hydrides are different due to one copper atom, which further proves that the coordination mode of hydrides is the key to efficient catalysis. Shen et al. successfully synthesized two bidentate NHC ligands and PA (phenylacetylide) co‐protected Au16 and Au17 with the same Au13 core. Au16 was formed by the Au13 core surrounded by three NHC‐Au‐PA OMs , one of which is independently uncoordinated. While the structure of Au17 was composed of four OMs coordinated to the Au13 core, of which there are two independent OMs. Au17 was 1.7 times more effective than Au16 in the hydroamination of alkynes under the same conditions, which was mainly because Au17 has one more independent OM than Au16.Sun et al. reported two amidinate‐protected stable copper hydride clusters (Cuidinate).32 The2.58n+4(SR)4n+8 with FCC structure 20, Au36(SR)24, Au44(SR)28). Au8n+4(SR)4n+8 NCs have the same surface motifs and periodically arranged cores with four (111) faces protected by dimer motifs and (100) faces  covered by bridging thiolates 20 > Au36(SR)24 > Au44(SR)28. In addition, the apparent activation energy of Au8n+4(SR)4n+8 is in the following sequence: Au28(SR)20 < Au36(SR)24 < Au44(SR)28, which further proves that Au28(SR)20 has excellent catalytic activity for alkyne hydration. Therefore, the catalysts have different core structures and electron‐accepting abilities resulting in the difference in affinities for alkynes. At the same time, (Au8n+4(SR)4n+8 20, Au36(SR)24, Au44(SR)28, Au52(SR)32) as a heterogeneous catalysts also exhibit excellent catalytic activity CO2 hydrogenation with different selectivity 24 produces formic acid as the main product, whereas Au28(SR)20 exhibits better methanol selectivity. The final product of Au44(SR)28 or Au52(SR)32 with a larger core is ethanol. This study provides a new idea for designing atomically precise catalysts by controlling the different core structures but the same motifs of gold nanoclusters to tune the performance of CO2 conversion.Proving catalytic active centers is a key step in understanding the reaction mechanism in the catalytic process, and exploring the active sites of NC catalysts has always been a research hotspot. Interestingly, when the surface protection nodes of the NCs are the same, whether the differences in their internal structures can affect the catalytic performance is a topic worthy of research by scientists. Sun and co‐workers reported a series of Aus Figure .q  NCs on the electrocatalytic activity of H2O2 from O2. The yield of [Au25(SC12H25)18]q as a catalyst for electrocatalytic oxygen to hydrogen peroxide can reach ∼ 90%, which is caused by the electron transfer from the anion Au25 core to the LUMO (π*) of O2.It is well known that the charge state of NCs will impact their electronic structure and change local bond length, which in turn determines their catalytic performance.114 Au1 orbital inside and outside of Au25q and explored its catalytic behavior for the intramolecular hydroamination of alkyne toward indole m NCs of different sizes. Although some interesting results have been made, more metal NCs of different sizes are still urgently needed for the in‐depth investigation of size‐dependent catalytic properties. The electronic properties of metal NCs can be modulated by the atom arrangement in the kernel, resulting in different catalytic performances. For example, Au38 and Au36 isomers as well as Au28 and Au25 quasi‐isomers, which have the same number of atoms but different atom arrangements, exhibit different catalytic activities. More interestingly, single‐atom dislodging/adding may have an important effect on the electronic structure of metal NCs, further showing an obvious change in catalytic properties. Therefore, the programmable kernel of metal NCs opens a new avenue for tailoring the catalytic performance on an atom‐by‐atom basis. Despite the advances in this field, there remain serious challenges including yield, stability, the blocked active metal sites by protected ligands, and the limited number of useful clusters, which further need more effort in the future to enable such catalysts to be used in industry. The purpose of this review is to look ahead to the potential challenges and opportunities in this emerging field, provide insightful guidance for the rational design and synthesis of atomically precise NCs catalysts, and lay a theoretical basis for understanding the correlation between structure and properties of NCs at the atomic level.This review highlights the most recent research progress in tailoring the catalytic activity and selectivity by precisely tuning the kernel structures of metal NCs, giving some insight into the influence of the size, and structural isomerism, of the metal NCs’ kernel structures on overall catalytic performance. Size‐dependent catalytic performance eventually began to study based on the successful synthesis of a series of AuThe authors declare no conflicts of interest.


Type 2 diabetes (T2D) prevalence in the 10‐ to 19‐year‐old population has doubled over the past two decades in the United States.The incidence of type 1 diabetes (T1D) in the United States also increased, from 20 to 22 per 100 000 persons age <20 during the same period,The numbers of youth with T1D and T2D in 2017 were 185 000 and 28 000, respectively, and, based on these increasing prevalence and incidence rates, the numbers are projected to be 335 000 youth with T1D and 220 000 with T2D in 2060, increases of 65% and 673%, respectively.Similarly, T2D and T1D in youth are increasing in incidence and prevalence worldwide. The number of youths with T2D is more than twice as great in China and 1.4‐fold higher in India than in the United States based on the larger population of these countries, but with the United States showing the highest reported prevalence in a recent worldwide survey (Table The prevalence of T1D among youth in Germany increased similarly from 1.4 per 1000 in 2002 to 2.5 per 1000 in 2020, and although T2D prevalence was considerably lower than in the United States, it again increased more markedly than T1D, from 0.03 to 0.11 per 1000.To some extent, the growth in T2D is driven by high rates of obesity. Some 20% of US adolescents aged 10–19 years are obese, with the prevalence increasing from 2000 to 2018 and with obesity rates greater among adolescents from households with lower income or lower parental educational level.Relatively poor glycemic control of youth both with T1D and T2D has been documented in the United States, with mean HbA1c between 8% and 9% and with trends for increasing levels over the past two decades.None.


Effectivenanozymes need to retain their activity in the face of surface speciationin biological environments, and characterizing surface speciationis therefore critical to understanding and controlling the therapeuticcapabilities of CeNPs. In particular, adsorbed phosphates can impactthe enzymatic activity exploited to convert phosphate prodrugs intotherapeutics in vivo and also define the early stagesof the phosphate-scavenging processes that lead to the transformationof active CeO2 into inactive CePO4. In thiswork, we utilize ab initio lattice-dynamics calculationsto study the interaction of phosphates with the three major surfacesof ceria and to predict the infrared (IR) and Raman spectral signaturesof adsorbed phosphate species. We find that phosphates adsorb stronglyto CeO2 surfaces in a range of stable binding configurations,of which 5-fold coordinated P species in a trigonal bipyramidal coordinationmay represent a stable intermediate in the early stages of phosphatescavenging. We find that the phosphate species show characteristicspectral fingerprints between 500 and 1500 cm–1,whereas the bare CeO2 surfaces show no active modes above600 cm–1, and the 5-fold coordinated P species inparticular show potential diagnostic P–O stretching modes between650 and 700 cm–1 in both IR and Raman spectra. Thiscomprehensive exploration of different binding modes for phosphateson CeO2 and the set of reference spectra provides an importantstep toward the experimental characterization of phosphate speciationand, ultimately, control of its impact on the performance of ceriananozymes.Cerium dioxide (CeO Wepredict the vibrational fingerprints of the surface-bound phosphatespecies by simulating IR and Raman spectra and demonstrate that thesespectroscopic techniques can be a sensitive probe for studying thesurface speciation and, therefore, establishing its impact on nanozymaticactivity.In order to predict and control the therapeutic activityof CeNPs,understanding the interaction of different surfaces with phosphatespecies is therefore crucial. In this work, we employ density-functionaltheory (DFT) calculations coupled with lattice-dynamics modeling toinvestigate the surface speciation of the major {100}, {110}, and{111} surfaces of CeO2ab initio simulation package (VASP) code.38 All calculations were carried out using the Perdew–Burke–Ernzerhof(PBE) generalized gradient approximation (GGA) exchange–correlationfunctional.40 A plane wave cutoff energy of500 eV was used, which gives total energies converged to 4 meV perCeO2 formula unit compared to a 20% larger cutoff. Theion cores were modeled using projector augmented-wave (PAW) pseudopotentials,42 with frozen cores of [Kr] for Ce and [He] for O and P. The electronlocalization in the Ce 4f orbitals was accounted for using the DFT+ U correction of Dudarev et al., and the degree ofdissociation observed in each of the models we prepared is listedin Table S2. Structure images were generatedusing VESTA.56As discussed below, for each surface,we attempted to prepare severalmodels with phosphate species in different binding configurations.In some cases, we found that phosphoric acid sometimes dissociatedfollowing adsorption 59 routines in VASP. The Raman activities werecomputed from the change in the macroscopic dielectric tensor whenthe atoms in the structure are displaced by ±5 × 10–3 Å along each normal-mode vector, with the tensorscomputed using DFPT. The method used to compute the Raman spectrafollows the approaches of Skelton et al.and Raman spectra of the bulk and surface modelswere simulated using the procedure outlined in ref . This uson et al. and Schil.. Although, for a given surface, the adsorption of phosphateis generally stronger than the adsorption of water, which has bindingenergies of around −0.5, −1.2, and −1.6 eV onthe {111}, {110}, and {100} surfaces, respectively,45 substitution effects would need to be considered in theliquid phase.61Although we mainly focus on spectroscopy, we also discussthe energetics for completeness. The adsorption energies and optimizedstructures of the phosphate configurations examined in this work arepresented in 3.1.1surf) in a trigonal bipyramidal configuration above the surface plane. Thisis most prominent in the {110}-5OP–1Osurf model,where the O atom is displaced by 0.74 Å compared to 0.21 and0.20 Å in the {111}-5OP–1Osurf and {100}-5OP–2Osurf models. These structural changes may be indicative ofan early stage of preferential phosphate scavenging, in which casethe results suggest that this is more facile at the {110} than the{111} and {100} surfaces. {110}/{111} faceting of flat {110} surfaceshas also been reported and is related to the ease of forming oxygenvacancies at the surface, i.e., of pulling oxygenatoms out of the surface, but without creating a vacancy.52 Based on this, it is possible that 5OP couldbe an intermediate in a surface scavenging mechanism . As of yet, 5OP species havenot been implicated experimentally, with only 4-fold coordinated Pspecies known to strongly adsorb to CeNPs.48 This is consistent with the 4OP species being predicted to havelarger binding energies than those of the 5OP species for a givensurface  onthe three surfaces of CeO2 is found to be more stable thanadsorption as a 5OP species  embed into the surfaceat the same height as the Osurf and bond to Ce ions toestablish the tridentate interaction. This leads to the strongestadsorption energy of Eads = −4.53eV compared to all of the other 4OP tridentate configurations. Unlikethe {100}-4OP–3Osurf and {111}-4OP–3Osurf configurations, which both have three direct Ce–Op bonds, the {110}-4OP–3Osurf configurationhas one Ce–Op bond and two hydrogen bonds. Theadsorption energy of −2.46 eV makes this configuration lessstable than the {110}-4OP–2Osurf configuration (−2.93eV), which has only one H bond to the surface, indicating that theH-bonding network formed by tridentate 4OP is not sufficient to stabilizethis configuration over the bidentate alternative.Weattempted to investigate three different adsorption configurationsof 4OP, identate2d–j.Thep bonds.The order of stability is {100}-4OP–2Osurf >{110}-4OP–2Osurf > {111}-4OP–2Osurf, i.e., the strongestbidentate adsorption occurs at the {100} surface.The bidentateadsorption of 4OP at all three surfaces shows a complexhydrogen bonding network and two direct Ce–Osurf, with a binding energy of −2.33eV, where a crowded H-bonding network prevents rearrangement to abidentate or tridentate configuration. All attempts to stabilize monodentate4OP species on the {110} and {111} surfaces resulted in spontaneousconversion to bidentate or tridentate configurations.The only stablemonodentate configuration found in our simulationsis {100}-4OP–1O3.2bulk and Osurf, respectively, and we furtherdistinguish the surface O directly bonded to P atoms in the 5OP configurationsas *Osurf. Finally, Op and OHp denotephosphoryl O and OH (hydroxyl) groups, OHsurf denotes asurface hydroxyl group, and Hsurf and Hp denotesurface and phosphoryl H atoms, respectively.We now consider the simulated IR and Raman spectraof the adsorbed phosphate species. For brevity, we use the followingnotation to describe the modes. The shorthand ν denotes stretchingmodes, δ bending, ρ rocking, ω wagging, sc scissoring,and t twisting modes. The subscripts s and as identify symmetric andasymmetric modes, where relevant, and we denote longitudinal (withinthe surface plane) and transverse (perpendicular to the surface plane)modes by L or T in parentheses. We denote bulk and surface O atomsas O3.2.1Table S4).The IR spectra of bulk ceria andthe bare stoichiometric {100}, {110}, and {111} surfaces are shownin 2 ], and the predictedfrequency is in excellent agreement with the experimental value of272 cm–1.63 The {111}and {100} stoichiometric surfaces  in aqueous solution,where there are a number of features between 800 and 1200 cm–1 2, and νP=Op; Figure S1).66The main features in the IR spectraof the surface models with adsorbed phosphates are summarized in 500 cm–1 4.44 This–1 , correspondingto the stretchingand wagging of the hydroxyl groups (νO–Hsurf/νO–Hp and ωO–Hp/ωO–Hsurf) and the predicted frequencies of these vibrations arein good agreement with the literature.65 We note, however, that the majority of the existing reports on theIR spectra of phosphate species, both from experimental67 and computational studies,65 are forisolated or aqueous phosphates and are therefore not directly comparableto our simulations, but can nonetheless still provide a useful pointof comparison. The largest difference we see between the adsorbedand free phosphates is that the ρOp–Hp signals from the absorbed phosphates appear at higher frequencies, viz. 500–1000 vs <400 cm–1  to occur above 500 cm–1 due to their being more constrained.The spectra also display peaks above 3000 cm400 cm–1 2.65 We asurf, the band at 695 cm–1 corresponds tothe νP–*Osurf, where *Osurf isthe surface oxygen atom directly bonded to P, and the frequency issimilar to that obtained in previous calculations using the similarPW91 + U exchange–correlation treatment.44 A similar, albeit weaker, band is seen in thespectrum of {100}-5OP–2Osurf at 680 cm–1, but not for {110}-5OP–1Osurf, which instead showsa very weak signal at 671 cm–1. We attribute thisto the weaker interaction between the phosphate and the {110} surfacedue to the pulling out of the *Osurf and resulting elongationof the Ce–*Osurf bonds.The IR spectra of 5-foldcoordinated P species (5OP) adsorbed onthe stoichiometric {100}, {110}, and {111} surfaces are shown in p signals are not seen in the spectraof the {111}-5OP–1Osurf44 and {110}-5OP–1Osurf configurations, whereas the{100}-5OP–2Osurf spectrum shows a weak band at 1197cm–1. We attribute this difference to the bidentateadsorption at this surface compared to the monodentate adsorptionat the {111} and {110} surfaces, as discussed above.νP–Op and δP–(OHp)2 modes giverise to features at 1046 and 1110cm–1, respectively, in the IR spectrum of the {111}-5OP–1Osurf configuration, in agreement with the literature.44 The {110}-5OP–1Osurf spectrumhas a δP–OHp band at 1043 cm–1 but no δP–(OHp)2 feature. The{110}-5OP–1Osurf and {100}-5OP–1Osurf spectra also display νasP–OHp signals at 1007 and 1005 cm–1, respectively.The δP–OHp bond (νP=Op) has been reported experimentally to occur at 1225–1230cm–1 in dimethyl methylphosphonate on the {111}CeO2 surface68 and at 1165–1178cm–1 in aqueous H3PO4.67 We predict this vibration to occur at 1250 cm–1 in an isolated H3PO4 molecule, which compareswell to the 1254 cm–1 predicted in a previous computationalstudy.44 For the 5OP structures, the directinteraction between phosphorus and a surface oxygen atom causes anelongation of the P=Op bond from 1.48 Å inH3PO4 to 1.55–1.59 Å in the 5OPstructures (Table S3), which leads to asuppression of the band intensity in the IR spectra of the surface-bound5OP species as reported in a previous study of phosphate adsorptionto the CeO2{111} surface.44The stretching of the P=O2 are shownin The IR spectra of the stable monodentate, bidentate, and tridentate4OP adsorptions on the three surfaces of CeOsurf, the band at 821 cm–1 is a complex modeinvolvingthe phosphate and hydroxyl groups , and is consistentwith previous PW91 + U calculations that only observedνP–Op for phosphates interacting with the{111} surface. A similar feature is observed in the {110}-4OP–3Osurf spectrum at 833 cm–1, but not in the{100}-4OP–3Osurf spectrum. We also do not see anyδP–OHp features above 900 cm–1, in contrast to the feature at 939 cm–1 predictedfor phosphate adsorbed to the {111} surface in previous work.44 We predict ρOp–Hp features at 948 and 965 cm–1 in the {111}-4OP–3Osurf and {100}-4OP–3Osurf spectra, but nocorresponding feature in the {110}-4OP–3Osurf spectrum.In the spectrum of tridentate {111}-4OP–3OsP–OHp bands in the region of796–830 cm–1 and νasP–OHp features between 853 and 927 cm–1. Althoughthe {111}-4OP–2Osurf and {111}-4OP–3Osurf spectra show similar vibrational signatures to those predictedin previous PW91 + U calculations,44 we predict a greater variety of stretching P–Op modes between 800 and 1300 cm–1, and wealso do not predict any P–Op bending modes in thisregion. This is supported by experimental67 and computational modeling65 studieson phosphoric acid in aqueous solution.The simulated IR spectra of the bidentate 4OP species all showνsurf is the onlystable monodentate adsorption configuration  dominate the spectrum above 2000 cm–1 and are more intense than the signals from 500 to 1500 cm–1, although the difference in intensity is not as pronounced as inthe spectra of isolated phosphates modeled using B3LYP.65 We attribute this to the interaction with theCeO2 surfaces restricting the atomic motion in the νP–Op and νP–OHp stretches and, consequently,affecting the polarizability.Unlike the IR spectra, the Ramanspectra of the adsorbed phosphates show low-intensity stretching modesin the phosphate fingerprint region from 500 to 1500 cm1 S8 and 6. The reelves cf.5. The Rap–Hp phosphate hydroxyl rocking modes are shifted to higher frequenciesof 916–1079 cm–1 compared to 158–376cm–1 in isolated phosphates . In contrast to the {110}-5OP–1Osurf and {100}-5OP–2Osurf spectra, the spectrum of the {111}-5OP–1Osurf configuration does not show a νasP–OHp. However, as the νsP–OHp for {111}-5OP–1Osurf is relatively weak, it maybe that νasP–OH simply has too low an intensityto feature in the simulated spectrum.The intensities of the νsurf modes of the {111}-5OP–1Osurf (cm–1) and {100}-5OP–2Osurf configurations(695 and 680 cm–1), although relativelyintense in the simulated IR spectra (Table S6), are weak in the Raman spectra (Table S7), highlighting the complementarity between these two techniques.Finally, the νP–*O2 NPs with 1 M NaH2PO4 resultsin the appearance of a weak Raman signal at 965 cm–1, which was assigned to symmetric stretching of the adsorbed phosphateions.70 We predict the Raman-active symmetricstretching modes of all our configurations to lie between 750 and1077 cm–1, and that these overlap with the asymmetricstretching modes between 904 and 1160 cm–1.In experiments, treating agglomerates of 3–4 nm stoichiometricCeO–1 than those on the {110} and {111} surfaces. This could be due tothe polar nature of the {100} surface, where surface oxygen atomscan rearrange to accommodate adsorbates. The higher intensity of theRaman signals of the {100} 4OP configurations at the surfaces maytherefore serve as a characteristic fingerprint for phosphate adsorptionin experimental measurements.Notably, the spectra of the 4OP configurations on the {100} surfaceshow stronger features between 500–1500 cm42 nanozymesand, in particular, highlights the role of modeling in predictingand assigning spectroscopic bands.In summary, this studydemonstrates that IR and Raman spectroscopyare potential diagnostic tools to determine the presence and bindingmodes of phosphate species on the surface of CeOOur calculations show thatphosphates can interact with ceria inboth 5-fold coordinated trigonal bipyramidal and 4-fold coordinatedtetrahedral configurations. The 5-fold coordinated species are stablebut higher in energy than the 4-fold coordinated species and may representhigh-energy intermediates during the removal of O atoms from the surfacein the phosphate scavenging of ceria nanozymes. This could be investigatedusing molecular-dynamics simulations, but such simulations are beyondthe scope of this work. Among the 4-fold coordinated configurations,binding modes that maximize the interaction between the phosphateand the surface are consistently more stable for a given surface,with tridentate configurations being the most energetically favorable.–1, corresponding to the rocking ofthe surface Ce–O bonds where the oxygen atoms move out of thesurface plane and also has strong Raman stretching signals around180 cm–1 that are not seen in the spectra of theother surfaces. These signals are indicativeof the ease with which surface oxygen atoms can be removed from theflat {110} surface and its facile predisposition to facet into {111}/{110}surfaces.52 The simulated IR spectra ofthe adsorbed phosphates show characteristic fingerprints between 500and 1500 cm–1. In this region, the trigonal bipyramidalconfigurations show a distinct νP–*Osurf signalbetween 650 and 700 cm–1 due to the interactionbetween the phosphorus and surface oxygen atoms, and this signal canpotentially be used to identify such species experimentally. In general,we also find that while diagnostic features tend to be associatedwith strong signals in the IR spectra, they are often weaker in Ramanspectra, which may make it challenging to identify and distinguishdifferent phosphate species using Raman measurements.The simulated spectra show features related to both the surfaceand the bulk. Notably, the {110} surface has a unique IR signal at∼280 cm2 nanozymes, and future workshould focus on more complex and realistic models, e.g., taking intoaccount surface coverage and morphology and/or implicit or explicitsolvent effects.Overall,this study provides a “stepping-stone” towardusing IR and Raman spectroscopy as a diagnostic tool for characterizingthe surface speciation of CeO


II molecule‐based compound, 2](BF4)2[Fe(1bpp). Large atomic displacements resulting from Jahn–Teller distortions induce a change in the molecule dipole moment when switching between high‐spin and low‐spin states leading to a step‐wise change in the electric polarization and dielectric constant. For temperatures in the region of bistability, the changes in magnetic and electrical properties are induced with a remarkably low magnetic field of 3 T. This result represents a successful expansion of magnetoelectric spin crossovers towards ambient conditions. Moreover, the observed 0.3–0.4 mC m−2 changes in the H‐induced electric polarization suggest that the high strength of the coupling obtained via this route is accessible not just at cryogenic temperatures but also near room temperature, a feature that is especially appealing in the light of practical applications.Magnetoelectric coupling is achieved near room temperature in a spin crossover Fe II molecule‐based compound. The coupling is realized through the interplay of structural, magnetic, and electrical changes that allows the spin crossover to be driven by a remarkably low magnetic field of 3 T.Magnetoelectric coupling is achieved near room temperature in a spin crossover Fe While the field‐induced changes of ϵ′ and ΔP occur in a similar temperature window as the ones observed for M(H)  at the SCO is of a similar order of magnitude as in previously reported magnetoelectric materials, Mn(taa),2323]BPh4,2323]BPh4,2+‐based material. As noted before, the origin of ΔP is the structural transition that significantly deforms the molecule in the polar P21 space group setting. Based on these structural changes and different spin states (S=0 and S=2) of 2](BF4)2(BF4)2(BF4)2[Fe(1bpp) represents an important example showing that SCO transitions can be utilized to achieve strong magnetoelectric coupling regardless of the transition temperature—the feature that holds promise for potential applications. In 2](BF4)2(BF4)2[Fe(1bpp) occurs between phases of the same polar space group P21  indicating that large atomic displacements changing the value of electric polarization in neighboring phases are sufficient for the observation of the coupling.To summarize, we have demonstrated strong magnetoelectric coupling at 260 K in the SCO compound, The authors declare no conflict of interest.1As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.