Applied Catalysis2022，Vol.30210.DOI:10.1016/j.apcatb.2021.120834

Role of surface steps in activation of surface oxygen sites on Ir nanocrystals for oxygen evolution reaction in acidic media

Kim, Chang-Hee Feng, Zhenxing Kim, Byung-Hyun Lee, Seung Woo Kim, Myeongjin Park, Jinho Wang, Maoyu Wang, Qingxiao Kim, Moon J. Kim, Jin Young Cho, Hyun-Seok
Applied Catalysis2022，Vol.30210.DOI:10.1016/j.apcatb.2021.120834
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  • NSTL
  • Elsevier

Role of surface steps in activation of surface oxygen sites on Ir nanocrystals for oxygen evolution reaction in acidic media

Kim, Chang-Hee 1Feng, Zhenxing 2Kim, Byung-Hyun 1Lee, Seung Woo 3Kim, Myeongjin 4Park, Jinho 3Wang, Maoyu 2Wang, Qingxiao 5Kim, Moon J. 5Kim, Jin Young 6Cho, Hyun-Seok1
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作者信息

  • 1. Korea Inst Energy Res
  • 2. Oregon State Univ
  • 3. Georgia Inst Technol
  • 4. Kyungpook Natl Univ
  • 5. Univ Texas Dallas
  • 6. Korea Inst Sci & Technol KIST
  • 折叠

Abstract

Ir and its oxide are the only available oxygen evolution reaction (OER) electrocatalysts with reasonably high activity and stability for commercial proton-exchange membrane electrolyzers. However, the establishment of structure-performance relationships for the design of better Ir-based electrocatalysts is hindered by their uncontrolled surface reconstruction during OER in acidic media. Herein, we monitor the structural evolution of two model Ir nanocrystals (one with a flat surface enclosed by (100) facets and the other with a concave surface containing numerous high-index planes) under acidic OER conditions. Operando X-ray absorption spectroscopy measurements reveal that the promotion of surface IrOx formation during the OER by the concave Ir surface with high-index planes results in a gradual OER activity increase, while a decrease in activity and limited oxide formation are observed for the flat Ir surface. After the activation process, the Ir concave surface exhibits similar to 10 times higher activity than the flat surface. Density functional theory computations reveal that Ir high-index surfaces are thermodynamically preferred for the adsorption of oxygen atoms and the formation of surface oxides under OER conditions. Thus, our work establishes a structure-performance relationship for Ir nanocrystals under operating conditions, providing new principles for the design of nanoscale OER electrocatalysts.

Key words

Electrocatalysts/Oxygen evolution reaction/Operando X-ray absorption spectroscopy/Density functional theory/Ir nanocrystals/INITIO MOLECULAR-DYNAMICS/TOTAL-ENERGY CALCULATIONS/DURABILITY/OXIDATION/ELECTROCATALYSIS/DISSOLUTION/CATALYSTS/INSIGHTS/METALS/PH

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出版年

2022
Applied Catalysis

Applied Catalysis

ISSN：0926-3373
被引量21
参考文献量60
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