Solar-Powered Interfacial Evaporation for Simultaneous Photocatalytic Hydrogen Production and Salinity Gradient Power Generation

Solar-driven interfacial evaporation desalination technology offers a feasible solution to the global shortage of freshwater resources. However, previous interfacial evaporation technologies have often only focused on the production of freshwater resources, without fully utilizing the high-energy photons in sunlight and the salinity gradient generated after seawater evaporation. In this work, a solar-driven water–hydrogen–electricity (SWHE) co-production system integrated by solar-driven interfacial evaporation (SIE), interface photocatalytic hydrogen evolution (IPHE), and reverse electrodialysis (RE) was proposed. The aim is to enhance the efficiency of solar energy utilization and achieve simultaneous production of freshwater, hydrogen, and electricity. Under 2-sun irradiation, the SWHE device achieved a water generation rate of 0.77 kg m−2 h−1, a hydrogen generation rate of 8.57 mmol m−2 h−1, and a highest power density of 2.9 mW m−2. Outdoor tests demonstrate that the cumulative water production reached 1.6 kg m−2 over 6 h, with a total hydrogen yield of 12.22 mmol m−2 and a highest power density of 0.095 mW m−2, which validated the environmental adaptability of SWHE system. This novel design strategy is expected to provide a novel form of freshwater resources and energy supply for human society.