Interface engineering of iron-doped multiphase nickel hydroxide as an effective electrocatalyst for oxygen evolution reaction

Abstract

The exploration of catalysts for oxygen evolution reaction (OER) using the advantages of interface engineering is an attractive strategy for achieving highly efficient electrochemical water splitting. In this study, Fe-doped multiphase nickel hydroxide (Fe-α,β-Ni(OH)2) was successfully prepared with a unique interface by modulating the Fe2+ and Fe3+ ratios in a feasible one-step hydrothermal process. This multiphase catalyst powder significantly contributed to the OER performance, with a low overpotential of 259 mV at 10 mA cm−2 (grown on carbon cloth substrates, 260 mV at 100 mA cm−2) and excellent catalytic stability during the 70-h OER process under extreme conditions. Based on the experimental and theoretical results, the unique interface between the Fe-α-Ni(OH)2 and Fe-β-Ni(OH)2 phases optimized the adsorption free energies of oxygen-containing intermediates and accelerated the formation of Ni3+ active species during the OER, leading to a large electrochemically active surface area (ECSA), which considerably enhanced the OER performance. This study provides novel insight into interface engineering and the design of high-performance OER catalysts based on earth-abundant transition-metal elements.