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Grain Boundaries Boost Oxygen Evolution Reaction in NiFe Electrocatalysts
Author(s) -
Park Hoon Kee,
Ahn Hehsang,
Lee Tae Hyung,
Lee Jae Yoon,
Lee Mi Gyoung,
Lee Sol A.,
Yang Jin Wook,
Kim Sang Jun,
Ahn Sang Hyun,
Kim Soo Young,
Lee ChulHo,
Park Eun Soo,
Jang Ho Won
Publication year - 2021
Publication title -
small methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.66
H-Index - 46
ISSN - 2366-9608
DOI - 10.1002/smtd.202000755
Subject(s) - oxygen evolution , grain boundary , crystallite , materials science , catalysis , electrochemistry , transmission electron microscopy , oxygen , chemical engineering , nanotechnology , chemistry , metallurgy , electrode , microstructure , biochemistry , organic chemistry , engineering
In a polycrystalline material, the grain boundaries (GBs) can be effective active sites for catalytic reactions by providing an electrodynamically favorable surface. Previous studies have shown that grain boundary density is related to the catalytic activity of the carbon dioxide reduction reaction, but there is still no convincing evidence that the GBs provide surfaces with enhanced activity for oxygen evolution reaction (OER). Combination of various electrochemical measurements and chemical analysis reveals the GB density at surface of NiFe electrocatalysts directly affects the overall OER. In situ electrochemical microscopy vividly shows that the OER occurs mainly at the GB during overall reaction. It is observed that the reaction determining steps are altered by grain boundary densities and the meaningful work function difference between the inside of grain and GBs exists. High‐resolution transmission electron microscopy shows that extremely high index planes are exposed at the GBs, enhancing the oxygen evolution activity. The specific nature of GBs and its effects on the OER demonstrated in this study can be applied to the various polycrystalline electrocatalysts.