Hollow Ag/MnO2 Nanostructures with Controllable Shells: Synthesis and Oxygen Reduction Reaction Catalytic Performance.
Novel hollow Ag/MnO2 nanostructures with controlled shell composition and structure were designed and synthesized. In the present synthetic procedure, silver nanocrystals were oxidized by KMnO4 , and MnO2 was heterogeneously formed on the surface of silver nanocrystals, then released Ag+ was photoreduced to silver adjacent to MnO2 . By simply changing the photoreduction moment, simultaneously with or after the addition of KMnO4 , hollow Ag/MnO2 structures with different shell architectures-a monolayered shell composed of evenly mixed silver and MnO2 and a double-layered shell composed of an inner MnO2 layer and an outer silver layer-can be obtained. Furthermore, the morphology of the hollow structure can be tuned by selecting different silver precursors, and the ratio of silver to MnO2 in the shell can also be controlled by adjusting the ratio in the original reaction mixture. Electrochemical measurements revealed significantly enhanced catalytic performance in the oxygen reduction reaction for the prepared hollow structures. Compared with the Ag/MnO2 composite, the onset potentials positively shift by about 50.0 mV and limiting current densities are nearly 2.0 times higher.
['Zhao|Xinfu|X|', 'Chen|Bo|B|', 'Jiao|Xiuling|X|', 'Zhang|Jian|J|', 'Pang|Yingping|Y|', 'Chen|Dairong|D|']
nanostructures silver electrochemistry redox chemistry synthesis design