Microwave-assisted synthesis of the cobalt-iron phosphates nanosheets as an efficient electrocatalyst for water oxidation

Electrochemical water splitting involves two half-cell reactions, that is oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), and the overall reaction is severely restricted by the OER sluggish kinetics. Hence, to design and develop superior active and low-cost OER electrocatalyst is of significant necessary. In this study, the bimetallic cobalt-iron phosphates nanosheets (denoted as Co-Fe-P-O) with high activity toward OER has been constructed via a rapid microwave-assisted process using sodium hypophosphite and ethylene glycol as the phosphorus source and reaction solvent, respectively. Due to the structural feature of a larger electrochemical active surface area, the catalyst exerts a small overpotential of 267 mV at a current density of 10 mA cm−2 and a low Tafel slope of 30 mV dec−1 in 1.0 M KOH solution. The as-prepared catalyst also shows an outstanding stability with a current density retention of 94% at a constant water oxidation for almost 10 h. All of the results suggest that the performance of the catalyst prepared in our work is better than the state-of-the-art commercial RuO2 and even can rival most of transition metal-based material.