Hydroxyl radical dominated photocatalytic degradation of sulfamethazine by BaTiO3/Cu2O: mechanism and intermediate product analysis

This study employed a liquid-phase reduction method to prepare BaTiO 3 /Cu 2 O heterojunction photocatalysts for the efficient degradation of antibiotics in aqueous solutions. The effective fabrication of the heterojunction addresses the limited photogenerated charge separation efficiency inherent in Cu 2 O, thereby augmenting the photocurrent density of the photocatalyst and diminishing the surface transfer impedance. Concurrently, the reduced photoluminescence intensity serves as an indicator of the superior charge transfer efficiency. During the photocatalytic degradation of sulfamethazine (SMZ) using BaTiO 3 /Cu 2 O heterojunction catalysts, · O 2 - and ·OH radicals play a primary role. Compared to Cu 2 O, the degradation rate of SMZ reached 77.5 % within 100 min, representing a 2.1-fold increase. Based on band structure calculations, a photocatalytic degradation mechanism and enhancement mechanism were proposed. Intermediate products of the degradation process were identified and evaluated for biotoxicity. Potential degradation pathways were proposed, corroborating that the photocatalytic degradation process demonstrates an environmentally friendly, low-toxicity trend. This study serves as a reference for the future development of high-performance photocatalysts responsive to visible light.