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Hollow Ag/MnO 2 Nanostructures with Controllable Shells: Synthesis and Oxygen Reduction Reaction Catalytic Performance
Author(s) -
Zhao Xinfu,
Chen Bo,
Jiao Xiuling,
Zhang Jian,
Pang Yingping,
Chen Dairong
Publication year - 2017
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201601485
Subject(s) - nanocrystal , catalysis , nanostructure , materials science , electrochemistry , shell (structure) , chemical engineering , oxygen , composite number , layer (electronics) , nanotechnology , redox , electrode , chemistry , composite material , metallurgy , biochemistry , engineering , organic chemistry
Novel hollow Ag/MnO 2 nanostructures with controlled shell composition and structure were designed and synthesized. In the present synthetic procedure, silver nanocrystals were oxidized by KMnO 4 , and MnO 2 was heterogeneously formed on the surface of silver nanocrystals, then released Ag + was photoreduced to silver adjacent to MnO 2 . By simply changing the photoreduction moment, simultaneously with or after the addition of KMnO 4 , hollow Ag/MnO 2 structures with different shell architectures—a monolayered shell composed of evenly mixed silver and MnO 2 and a double‐layered shell composed of an inner MnO 2 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 MnO 2 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/MnO 2 composite, the onset potentials positively shift by about 50.0 mV and limiting current densities are nearly 2.0 times higher.