Hierarchical CoFe oxyhydroxides nanosheets and Co2P nanoparticles grown on Ni foam for overall water splitting

The development of industrial application of water splitting demands simple and effective methods for the preparation of highly efficient electrocatalysts that are inexpensive and robust. Herein, we report a simple activation method to decorate 3D cobalt iron oxyhydroxide (CoFe-OOH) nanosheets on Co 2 P nanoparticles with Ni foams (NF) as substrates. The synthesized catalysts exhibit excellent activity for electrochemical oxygen evolution reaction due to the hierarchical heterostructures and synergistic effects of CoFe-OOH and Co 2 P. The as-prepared catalysts require a low overpotential of 199 mV to deliver 30 mA cm −2 in oxygen evolution reaction in 1 M KOH with a small Tafel slope of 39 mV dec −1 , indicating favorable kinetics during electrolysis. The synthesized catalysts are further used as cathode and anode for overall water splitting, which only requires a cell voltage of 1.60 V at a current density of 30 mA cm −2 . This work provides new insights on the preparation of efficient electrocatalysts for overall water splitting, which may have the potentials for industrial water electrolysis.