author | Kwangyeol Lee |
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Homepage | http://nanolab.korea.ac.kr/ |
journal | Matter |
The layered transition metal oxyhydroxides have received increasing interest owing to the efficient energy conversion performance and material stability during the oxygen evolution reaction (OER). In particular, Fe-doped NiOOH has shown record-high OER performance in alkaline media among various catalysts. Theoretically, undercoordinated facets including Ni4+, exposed at the edges of NiOOH, were predicted to perform highly active OER. Therefore, here we suggest a rational catalyst design, a vertical-crystalline β-Fe/NiOOH layer built on faceted Fe/Ni nanocrystals, which exposes Ni4+ sites and could improve the OER performance dramatically. Electrochemical OER tests recorded the overpotential of 210 mV at a current density of 10 mA cm−2GEO and stable operation for 5 days. In situ/operando and density functional theory studies revealed that the Ni valence cycle between +2 and +4 assisted by Fe dopant is the key engine that greatly accelerates OER kinetics and that the vertical-crystalline β-Fe/NiOOH layers on Ni octahedra are stable under harsh OER conditions.
https://www.sciencedirect.com/science/article/abs/pii/S2590238521004483?dgcid=author
Byungyun Kim
(First author, Institute for Basic Science)
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