Amorphous high entropy oxides based on polyoxometalate clusters to accelerate surface reconstruction for oxygen evolution reaction

Abstract

High-entropy materials (HEMs) with unique electronic structures and diverse elemental compositions have emerged, however, HEMs are complicated to prepare. Here, we prepared an amorphous FeCoNiMoW high-entropy oxide (FCNMWO) catalyst by simple one-pot hydrothermal preparation, based on a method that used polyoxometalate clusters as metal cation linkers. The FCNMWO with amorphous structure exhibited better oxygen evolution reaction, as confirmed by a series of characterization and electrochemical experiments, which exhibited a low overpotential of 313 mV at a current density of 10 mA cm−2 with a Tafel slope of 40.95 mV dec−1, indicating excellent charge transfer capability. Moreover, the presence of polyoxometalate clusters modulated the electronic structure and accelerated charge transfer processes, promoting OER property. In addition, analysis of the results before and after OER stability revealed that the leaching of Mo induced reconstruction on the catalyst surface, and the MOOH were actual active species. This work is instructive for further design and development of efficient high entropy electrocatalysts with admirable OER properties.