High crystallinity design of Ir-based catalysts drives catalytic reversibility for water electrolysis and fuel cells
SCIE
SCOPUS
- Title
- High crystallinity design of Ir-based catalysts drives catalytic reversibility for water electrolysis and fuel cells
- Authors
- Lee, Woong Hee; Ko, Young-Jin; Kim, Jung Hwan; Choi, Chang Hyuck; Chae, Keun Hwa; Kim, Hansung; Hwang, Yun Jeong; Min, Byoung Koun; Strasser, Peter; Oh, Hyung-Suk
- Date Issued
- 2021-07
- Publisher
- Nature Publishing Group
- Abstract
- AbstractThe voltage reversal of water electrolyzers and fuel cells induces a large positive potential on the hydrogen electrodes, followed by severe system degradation. Applying a reversible multifunctional electrocatalyst to the hydrogen electrode is a practical solution. Ir exhibits excellent catalytic activity for hydrogen evolution reactions (HER), and hydrogen oxidation reactions (HOR), yet irreversibly converts to amorphous IrOx at potentials > 0.8 V/RHE, which is an excellent catalyst for oxygen evolution reactions (OER), yet a poor HER and HOR catalyst. Harnessing the multifunctional catalytic characteristics of Ir, here we design a unique Ir-based electrocatalyst with high crystallinity for OER, HER, and HOR. Under OER operation, the crystalline nanoparticle generates an atomically-thin IrOx layer, which reversibly transforms into a metallic Ir at more cathodic potentials, restoring high activity for HER and HOR. Our analysis reveals that a metallic Ir subsurface under thin IrOx layer can act as a catalytic substrate for the reduction of Ir ions, creating reversibility. Our work not only uncovers fundamental, uniquely reversible catalytic properties of nanoparticle catalysts, but also offers insights into nanocatalyst design.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/115470
- DOI
- 10.1038/s41467-021-24578-8
- ISSN
- 2041-1723
- Article Type
- Article
- Citation
- Nature Communications, vol. 12, no. 1, 2021-07
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