Abstract
In this study, we successfully synthesized a graphitic carbon nitride/bismuth oxybromide (g-C3N4/BiOBr) heterojunction photocatalyst via a facile hydrothermal-precipitation method and evaluated its performance for the degradation of tetracycline (TC) under visible light irradiation. The physical, optical, and structural properties of the synthesized materials were thoroughly characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The g-C3N4/BiOBr composite exhibited superior photocatalytic activity compared to bare g-C3N4 and pristine BiOBr. Specifically, the optimal composite containing 20 wt% g-C3N4 achieved a tetracycline degradation efficiency of 92.4% within 120 minutes of visible-light exposure, which is approximately 3.1 and 2.4 times higher than that of pure g-C3N4 and BiOBr, respectively. This enhanced photocatalytic performance is primarily attributed to the formation of a well-aligned staggered type-II heterojunction, which significantly accelerates the separation and migration of photogenerated electron-hole pairs. Radical scavenging experiments indicated that superoxide radicals (•O2-) and holes (h+) played a dominant role in the degradation process. Furthermore, the catalyst demonstrated excellent stability and reusability over four successive cycles. This work offers a promising, cost-effective strategy for the design of highly efficient heterostructured photocatalysts aimed at the remediation of pharmaceutical contaminants in aquatic environments.
