Step-scheme heterojunction g-C3N4/TiO2 for efficient photocatalytic degradation of tetracycline hydrochloride under UV light

Construction of heterojunction between semiconductors is considered an effective strategy for enhancing photocatalytic capability. Herein, this work prepared an abundant porous g-C3N4/TiO2 photocatalyst, with the two-dimensional (2D) nanosheet g-C3N4 and nanoparticle TiO2. The heterojunction both enhanced the ultraviolet (UV) light absorption ability, and inhibited the recombination of photogenerated electron-hole (h+) pairs. As expected, the optimal 4 % g-C3N4/TiO2 (g-C3N4:TiO2 = 1:25) exhibited a prominent degradation efficiency of 96.53 % in the photocatalytic performance of tetracycline hydrochloride (TCH) under UV irradiation. The recycling of the heterojunction photocatalyst g-C3N4/TiO2 remained stability and reusability. The main active species were·O2-, h+ and·OH, and the formation of internal electric field on the step-scheme (S-scheme) heterojunction interface accelerated the migration of photogenerated carriers. Moreover, several environmental factors on degradation such as dose, pH, and the initial concentration of TCH were investigated. This work could be spread to the conceive of other S-scheme heterojunction photocatalysts in application to different environmental demands.