Three-phase interface engineering via P-doped CoMo2S4-integrated Co4S3/Co2P enables high-efficiency overall water splitting

In this research, we constructed a three-phase interface derived from phosphorous-doped CoMo2S4 sheets integrated Co2P/Co4S3 hybrid heterostructure (P − CoMo2S4/Co4S3–Co2P) to form a high-efficiency electrocatalyst, which can promote both hydrogen and oxygen evolution in alkaline electrolyte. To attain a current density of 10 mA cm−2, P − CoMo2S4/Co4S3–Co2P requires an overpotential of only 54 mV for cathodic reaction, and 296 mV for anodic reaction. A two-electrode electrolyzer of P − CoMo2S4/Co4S3–Co2P(+,−) shows a low cell voltage of 1.55 V at 10 mA cm−2 and prospective durability of 95.6% performance retention after 50 h. Furthermore, a solar energy-powered water electrolysis system reveals an effective solar-to-hydrogen efficiency of 14.1%. The high catalytic performances are well understood by experiment and theoretical studies, which indicate the enhanced electroactive surface, rapid charge transfer, and optimum adsorption energy for promoting well the reaction kinetics. The achievements provide a promising high-performance electrocatalyst for green hydrogen generation by water splitting.