Grain Boundaries Boost Oxygen Evolution Reaction in NiFe Electrocatalysts

Hoon Kee Park, Hehsang Ahn, Tae Hyung Lee, Jae Yoon Lee, Mi Gyoung Lee, Sol A. Lee, Jin Wook Yang, Sang Jun Kim, Sang Hyun Ahn, Soo Young Kim, Chul Ho Lee, Eun Soo Park, Ho Won Jang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Article number2000755
JournalSmall Methods
Volume5
Issue number2
DOIs
Publication statusPublished - 2021 Feb 15

Keywords

  • electrocatalysts
  • grain boundaries
  • in situ electrochemical microscopy
  • NiFe alloys
  • oxygen evolution reaction

ASJC Scopus subject areas

  • Materials Science(all)
  • Chemistry(all)

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