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 weremiddotO(2-), h(+) andmiddotOH, 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.

Automated summary

Construction of heterojunction between semiconductors is an effective strategy to enhance the photocatalytic capability. In this study, a porous g-C3N4/TiO2 photocatalyst was prepared, consisting of two-dimensional nanosheet g-C3N4 and nanoparticle TiO2. The heterojunction enhanced UV light absorption and inhibited recombination of photogenerated electron-hole pairs. The optimal 4% g-C3N4/TiO2 exhibited a prominent degradation efficiency in the photocatalytic performance of tetracycline hydrochloride. The recycling of the heterojunction photocatalyst remained stable and reusable, with the main active species being O(2-), h(+), and OH. The formation of an internal electric field on the heterojunction interface accelerated the migration of photogenerated carriers. This study is of great importance for the design of other S-scheme heterojunction photocatalysts to meet different environmental demands.