Constructing Fe/Ni atomic interfaces in Fe-doped Ni(OH)2 with single-phase structures for efficient oxygen evolution

Abstract

Fe doping is acknowledged as an extremely efficient strategy for enhancing the catalytic performance in oxygen evolution reaction (OER). However, the influence of Fe distribution, except for the concentration, on OER catalysis remains vague. In particular, the key role of Fe/Ni atomic interfaces on the OER catalytic performance is rarely investigated. In this work, the relationship of atomically interfacial Fe and adjacent Ni activity in Fe-doped Ni(OH)₂ with Fe/Ni atomic interfaces is elucidated in detail via theoretical calculations. In this experiment, we innovatively made Fe aggregate locally to design a Ni/Fe atomic interface in a Fe-doped Ni(OH)₂ single-phase crystal structure. Various advanced characterization techniques revealed that the interfacial agglomerated Fe atoms can optimize the adjacent Ni electronic structure and distorted Ni/Fe–O octahedral structure, thereby confirming the obvious catalytic performance enhancement and the superiority of the Ni/Fe atomic interface over the homogeneous Fe distribution in Ni(OH)₂ for OERs. These fabricated Fe-doped-Ni–(OH)₂ with atomic interfaces show remarkable catalytic performance, exhibiting an overpotential of 248 mV at 10 mA cm⁻² with a Fe/Ni atom ratio of 1/10. This work sheds new light on interfaces at an atomic level for the catalytic performance enhancement of OERs.