Metal-Organic Frameworks-Derived Nickel-Iron Oxyhydroxide with Highly Active Edge Sites for Electrochemical Oxygen Evolution

Accurate introduction of catalytic active sites to precise locations on the catalyst surface is a challenge in designing and synthesizing high-efficiency catalysts. Herein, the alpha phase nickel-iron oxyhydroxide (alpha-NiFeOxHy) rich of nickel active edge sites is electrochemically in situ generated from Fe-square acid metal-organic framework precursor deposited on nickel-containing electrode matrixes, which revealed superior oxygen evolution reaction performance signified by an overpotential of 167 mV to achieve a current density of 10 mA cm(-2) in alkaline electrolytes. Notably, the as-prepared metal oxyhydroxide exhibits long-term electrochemical durability in 10 mA cm(-2) for over 1080 h. By integrating the electrochemical evidence, Mossbauer spectroscopy, X-Ray photoelectron spectroscopy, and density functional theory calculations, the nickel species enriched on the exposed edge facet of the as-synthesized alpha-NiFeOxHy are proposed to be the highly catalytic active site. This work provides an expedient and energy-efficient approach to in situ electrochemical fabrication of high-performance NiFeOxHy oxygen evolution reaction catalysts from metal-organic frameworks.