Solar-driven hydrogen and water co-generation based on atmospheric water harvesting

Solar-driven photocatalytic hydrogen production is considered to be a reliable, simple and effective technology for producing green hydrogen. However, a large amount of solar energy absorbed by the photocatalyst material is not utilized but directly dissipated into the atmosphere in the form of waste heat. Meanwhile, the dependence of photocatalytic hydrogen production system on the water supply chain also limits its promotion in water-scarce and arid areas. Herein, a solar-driven hydrogen and water co-generation (SHWC) device based on atmospheric water harvesting (AWH) technology is proposed. The integrated device consists of a water self-supply layer (WSL) and a photocatalytic layer (PL) for simultaneous hydrogen production and freshwater harvesting from the atmosphere. Under one sun illumination (1000 W m −2 ), the AWH-SHWC device obtains an average hydrogen production rate of 25.98 mmol m -2  h −1 with 81.78 g m -2  h −1 of condensate water. In the natural sunlight, 118.21 mmol m −2 day −1 of hydrogen production and 230 g m −2 day −1 of condensate water are obtained. At night, the WSL can achieve regeneration by adsorbing atmosphere water. This integrated device may offer a creative approach to addressing freshwater resource scarcity and the fossil energy crisis.