Anion doped bimetallic selenide as efficient electrocatalysts for oxygen evolution reaction

The development of highly efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) is of great importance in advancing the practical applications of green and sustainable hydrogen energy. Doping with either cations or non-metallic anions is a typical strategy used to improve the electrocatalytic activity for OER catalysts. In this study, an anion doped bimetallic selenide Co0.75Fe0.25(S0.2Se0.8)2 solid solution is prepared via the simultaneous sulfuration and selenylation of a scalably produced CoFe-layered double hydroxide (CoFe-LDH) precursor, using commercially available sulfur and selenium powders as S and Se sources, respectively. Electrocatalytic test shows that the anion doped bimetallic selenide Co0.75Fe0.25(S0.2Se0.8)2 electrode requires an overpotential of 293 mV and a low Tafel slope of 77 mV dec−1 at a current density of 10 mA cm−2 in an alkaline media, and it exhibits the significantly enhanced electrocatalytic performance for the OER compared with its counterparts of Co0.75Fe0.25S2 and Co0.75Fe0.25Se2. The enhanced electrocatalytic performance is supported experimentally by the results of charge-transfer resistance and electrochemically active surface area. Our LDH precursor-based protocol can provide a strategy to prepare non-metallic anion doped bimetallic selenides as efficient electrocatalysts for water splitting.