Construction of a SiO2-Sn3O4/g-C3N4 heterojunction with efficient visible-light-driven hydrogen evolution via a type-II charge transfer pathway

Utilizing solar energy for photocatalytic hydrogen production provides a promising pathway for sustainable energy conversion. However, the traditional photocatalyst has the defects of excessive charge recombination speed and poor stability. In this work, a series of Si-Sn 3 O 4 /g-C 3 N 4 heterojunction catalysts were synthesized via a facile ultrasonic-assisted thermal treatment method. The optimized Si-Sn 3 O 4 -5/CN composite exhibited a remarkable hydrogen evolution rate of 5295 μmol∙g −1  h −1 under visible light, which is 2.21 and 54 times higher than that of pure g-C 3 N 4 and Si-Sn 3 O 4 , respectively. Extensive characterization (XPS, PL, EIS, etc.) confirmed the formation of a Type-II heterojunction, which significantly promotes charge separation and transfer. Furthermore, the composite demonstrated excellent photocatalytic stability over four consecutive cycles. This work offers an efficient and stable photocatalyst system for solar-driven hydrogen production and sheds light on the design of heterostructured photocatalysts.