Modulating Electronic Structure of Iridium Single-Atom Anchored on 3D Fe-Doped β-Ni(OH)2 Catalyst with Nanopyramid Array Structure for Enhanced Oxygen Evolution Reaction

Abstract

Developing high-performance electrocatalysts for oxygen evolution reaction (OER) is crucial in the pursuit of clean and sustainable hydrogen energy, yet still challenging. Herein, a spontaneous redox strategy is reported to achieve iridium single-atoms anchored on hierarchical nanosheet-based porous Fe doped β-Ni(OH)₂ pyramid array electrodes (SAs Ir/Fe-β-Ni(OH)₂ ), which exhibits high OER performance with a low overpotential of 175 mV at 10 mA cm^-2 and a remarkable OER current density in alkaline electrolyte, surpassing Fe-β-Ni(OH)₂ /NF and IrO₂ by 31 and 38 times at 1.43 V versus RHE, respectively. OER catalytic mechanism demonstrates that the conversion of ^* OH→^* O and the active lattice O content can be significantly improved due to the modulation effect of the Ir single atoms on the local electronic structure and the redox behavior of FeNi (oxy) hydroxide true active species. This work provides a promising insight into understanding the OER enhancement mechanism for Ir single-atoms modified FeNi-hydroxide systems.

Keywords: Fe doped β-Ni(OH)2 nanosheet; direct O─O bond coupling; oxygen evolution reaction; single-atom iridium; spontaneous redox strategy.