▎ 摘　　要

Development of high-performance nonprecious metal-based catalysts for oxygen evolution reaction (OER) is crucial to improve the efficiency of water electrolysis and photoelectrochemical water splitting for harvesting and storage of solar energy. Herein, Co-Fe phosphates and their composites with reduced graphene oxide (rGO) were prepared by a simple hydrothermal method, which then acted as oxygen evolution reaction catalysts. In 1.0 M KOH aqueous solution, the as-obtained optimal composite, Co-Fe phosphate/rGO, can catalyze oxygen evolution reaction with a very sharp onset potential and a small over-potential of 338 mV to achieve a current density of 10 mA cm(-2). It was found that in these Co-Fe phosphates, the optimal Co:Fe ratio is 0.75:0.25. The excellent electrocatalytic performance of the Co-Fe phosphate/rGO composite would benefit from the synergistic effects between Fe and Co species, as well as rGO substrate providing conductive channels. The formed Co-Fe phosphate/rGO electrocatalysts can be the promising replacement of precious metal-based catalysts for more practical and cost-efficient water splitting.