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 a phase nickel-iron oxyhydroxide ( a -NiFeO x H y ) with rich of nickel active edge sites was 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 195 mV to achieve a current density of 10 mA cm −2 in alkaline electrolytes. Notably, the as-prepared metal oxyhydroxide exhibited long-term electrochemical durability in 10 mA cm −2 for over 1000 hours. By integrating the electrochemical evidence, Mössbauer spectroscopy, X-ray photoelectron spectroscopy and density function theory calculations, the nickel species enriched on the exposed edge facet of the as-synthesized a -NiFeO x H y were 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 NiFeO x H y OER catalysts from MOFs.