ZnIn₂S₄/CoAl₂O₄ p-n junction for photocatalytic hydrogen evolution

Addressing the environmental crisis stemming from fossil fuel overexploitation necessitates the development of efficient photocatalysts for clean hydrogen production. Herein, a novel ZnIn₂S₄/CoAl₂O₄ (ZIS/CAO) p-n junction photocatalyst was successfully fabricated by coating ZIS onto CAO nanosheets via a facile oil bath method. The exceptional light absorption capacity and electrical conductivity of CAO synergistically enhance the photocatalytic activity of ZIS. The established p-n junction facilitates efficient electron transfer from CAO to ZIS, significantly suppressing the recombination of photogenerated electron-hole pairs. Comprehensive characterization, including optical analyses, electrochemical measurements, in situ XPS, in situ KPFM, and DFT calculations, unequivocally verified this interfacial charge transfer mechanism. The optimized ZIS/CAO composite exhibited a remarkable photocatalytic H₂ evolution rate of 3,260 μmol·g^-1·h^-1 (5.87 times higher than ZIS) as well as excellent stability. This work presents a promising strategy for constructing highly efficient photocatalytic hydrogen evolution systems.