A Trifunctional Ni-P/Fe-P Collaborated Electrocatalyst Enables Self-Powered Energy Systems.

Recently, extensive research efforts have been devoted to drive electrocatalytic water-splitting for hydrogen generation by electricity or solar cells. However, electricity from power grid and the intermittent property of sunlight inevitably brings about environmental pollution and energy loss. Thus, a novelty energy system for simultaneous generating H from solar energy and overcoming the intermittence of sunlight is highly desirable. Herein, a self-powered energy system with solar energy as the sole input energy is successfully assembled by integrated Zn-air batteries with stable output voltage, solar cells, and water splitting electrolyzer to efficient H production. Specially, the Zn-air batteries are charged by the solar cell to store intermitted solar energy as electricity during light reaction. Under unassisted light reaction, the batteries could release electric energy to drive H production. Therefore, the aim for simultaneous generating H and eliminating the restrictions of intermittent sunlight are realized. The solar-to-hydrogen efficiency and solar-to-water splitting device efficiency of the self-powered energy system are up to 4.6% and 5.9%, respectively. This work provides the novel design systems for H production and the usage of renewable energy.