Construction and performance regulation of TiO2/Bi2O3 photocatalyst with Z-scheme heterojunction

Composite photocatalysts with Z -scheme and S-scheme heterojunctions show promising application potential, yet their synthesis remains challenging due to immature construction techniques. In this study, commercial TiO 2 and calcined Bi 2 O 3 were used as raw materials. By regulating the oxygen vacancy concentration on the surfaces of TiO 2 and Bi 2 O 3 nanoparticles, and thereby modulating the surface energy levels of the TiO 2 and Bi 2 O 3 particles, a TiO 2 /Bi 2 O 3 composite photocatalyst with a Z -scheme heterojunction was constructed via a hydrothermal method. The results indicate that the metallic bismuth formed during hydrothermal treatment bridges Bi 2 O 3 and TiO 2 . At a Bi 2 O 3 -to-TiO 2 mass ratio of 9:100 (sample TB9), the composite catalyst achieves 99.5% degradation of methylene blue and retains excellent stability over five cycles. This work proposes a strategy for constructing heterojunction photocatalysts by modulating surface energy levels, offering a novel approach for developing efficient photocatalytic materials.