Solar-driven hydrogen production based on moisture adsorption-desorption cycle

Photocatalytic hydrogen production by water splitting is considered one of the most promising green hydrogen manufacturing technologies , but the actual outdoor deployment of this technology is limited by the availability of water feedstocks in geographical locations. An integrated device consisting of a photocatalytic layer and an atmospheric water harvesting material that can achieve in-situ photocatalytic water vapor splitting for hydrogen production by spontaneously capturing moisture from the air as a water feedstock is proposed herein. The integrated system has excellent photocatalytic and photothermal synergistic ability, low hydrogen diffusion resistance by interfacial photocatalysis , and high stability by isolating salts contamination. The system can achieve a hydrogen production rate of 425.4 μmol g −1 h −1 and a water vapor supply rate of 0.121 kg m −2 h −1 under one sun illumination , and has a water vapor adsorption rate of 0.03 kg m −2 h −1 under dark conditions in the laboratory. Furthermore, this hybrid device obtains a total hydrogen production of up to 3963.1 μmol g −1 in the real outdoor daytime and accomplishes water regeneration within 10 hours by capturing environmental moisture at night. This work provides a suitable solution for hydrogen production in areas with water scarcity or drought.