Elaborate design and construction of direct Z-scheme ZnIn₂S₄@BiYWO₆ heterojunction catalysts for efficient photocatalytic hydrogen production

Photocatalytic Hydrogen production as one of the effective ways to solve the future energy issues has recently become a research hotspot in the field of renewable energy. However, single-component photocatalysts have poor hydrogen production efficiency due to the narrow light-absorption range, susceptibility to photo-corrosion and low catalytic activity. Herein, novel heterojunction photocatalysts of ZnIn₂S₄@BiYWO₆ with different mass ratios were designed and synthesized using a facile two-step hydrothermal method. Experimental results and analyses show that these heterojunction catalysts exhibit extremely excellent photocatalytic performance for hydrogen production. Especially, the hydrogen production rate of 10ZnIn₂S₄-BiYWO₆ is 73 times higher than that of pure ZnIn₂S₄. Furthermore, enhanced photocatalytic mechanism and carrier transfer pathway in the heterojunction photocatalyst of ZnIn₂S₄@BiYWO₆ were deeply analyzed and explored in the paper, which confirmed that ZnIn₂S₄@BiYWO₆ is a direct Z-scheme heterojunction architecture. Within such a Z-scheme framework, the presence of a built-in electric field at the interface between ZnIn₂S₄ and BiYWO₆ as well as the energy band bending lead to the direct recombination of electrons and holes with low redox capacity, while keeping the electrons and holes with high redox capacity in each component. Consequently, the photocatalytic activity of the Z-scheme heterojunction system has been greatly enhanced. It is believed that the present work provides valuable guidance for the design and construction of novel Z-scheme heterojunction photocatalysts.