Novel ternary BiOI/g-C3N4/CeO2 catalysts for enhanced photocatalytic degradation of tetracycline under visible-light radiation via double charge transfer process

Abstract In this work, a novel visible-light-driven ternary BiOI/g-C3N4/CeO2 photocatalyst was successfully synthesized by calcination and hydrothermal treatment. The obtained ternary BiOI/g-C3N4/CeO2 had high photocatalytic performance for the degradation of tetracycline (TC) under visible-light irradiation. The samples were characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance (DRS) spectroscopy, and Fourier transform infrared spectroscopy (FT-IR), etc. The results indicated that 3 wt% BiOI/g-C3N4/CeO2 catalyst possessed the best photocatalytic activity (91.6%) among all the as-prepared samples. The enhanced photocatalytic activity could be attributed to a double charge transfer process between g-C3N4 and other catalysts in the ternary heterojunction, so that the separation of photogenerated electron–hole pairs was more effective. The as-prepared ternary sample also exhibited high stability after six cycles of the photodegradation reaction. Additionally, the active species (h+) were considered as the main reactive species during the degradation of TC. Based on the research results, a possible photocatalytic reaction mechanism for the BiOI/g-C3N4/CeO2 sample was proposed and discussed in detail.