Heterostructured Nitrogen and Sulfur Co-doped Black TiO2/g-C3N4Photocatalyst with Enhanced Photocatalytic Activity

Conventional titanium dioxide(TiO2) photocatalyst could absorb only ultraviolet light due to its wide bandgap. In this paper, black TiO(2)with narrow bandgap was prepared by introducing oxygen vacancies. Meanwhile, nitrogen(N) and sulfur(S) elements were doped to further broaden the visible light response range of TiO2(NS-BT), and then heterostructured N,S-doped black TiO2/g-C3N4(CN/NS-BT) was successfully constructed by easily accessible route. The formation of CN/NS-BT heterojunction structure increased the generation and separation efficiency of photogenerated electron-hole pairs, as well as accelerated the transfer rate of the carriers. The as-prepared CN/NS-BT exhibited excellent photocatalytic performance towards the degradation of Rhodamine B(RhB) under visible light irradiation with satisfactory stability. The apparent reaction rate constant of CN/NS-BT(0.0079) was 15.8-fold higher than that of commercial P25(0.0005). The structure, morphology, chemical composition and optical properties of the as-prepared CN/NS-BT were characterized by various analytical methods, and possible photocatalytic enhancement mechanism was proposed. Overall, CN/NS-BT composites look promising as photocatalytic material for future environmental treatment.