Porous carbon loaded with g-C3N4/CaMoO4 heterojunction for efficient degradation of tetracycline

The extensive therapeutic use of tetracycline (TC) in human and veterinary healthcare systems has resulted in notable environmental persistence, with detectable residues increasingly documented in aquatic ecosystems worldwide. While photocatalytic technology has been widely applied for TC degradation, improving the photocatalytic activity of catalysts remains a critical challenge. Improving charge separation efficiency is a key approach to enhance the activity of photocatalysts. In this work, we successfully coupled g-C 3 N 4 and CaMoO 4 on 3D porous carbon via a hydrothermal method. The photocatalytic properties of the composites were determined through the degradation of TC under visible light. Under simulated visible light irradiation, the results demonstrated that the g-C 3 N 4 /CaMoO 4 @C achieved 94.8% degradation of TC under 90 min of light exposure, significantly outperforming pure g-C 3 N 4 and pure CaMoO 4 , which achieved only 39.7% and 39.2% degradation in the same period. And the g-C 3 N 4 /CaMoO 4 @C achieved 73.59% removal of total organic carbon. The photocatalytic activity was investigated by adjusting key parameters, including TC solution pH, initial concentration, and catalyst dosage. The morphology, structure and composition of the catalysts were characterized by XRD, XPS and TEM characterization techniques, and the reasons for the improved performance of the composite photocatalysts were analyzed by combining the results of UV-Vis and PL characterizations, and the photocatalytic mechanism of the catalysts was further explored by ESR characterization.