Heterogeneous photo-Fenton degradation of metronidazole using novel g-C 3 N 4 /LaFe 0.5 Cu 0.5 O 3− δ under visible light

A novel g-C 3 N 4 /LaFe 0.5 Cu 0.5 O 3− δ (CN/LFCO) heterogeneous catalyst with dual functions of photocatalysis and Fenton oxidation was prepared for metronidazole (MNZ) degradation. The obtained materials were characterized by XRD, XPS, and DRS to investigate the mechanism for the enhanced performance of the photo-Fenton catalyst. A single-variable experiment was used to determine the optimal reaction conditions, cycling experiments, and ion-leaching tests to ascertain the stability of CN/LFCO(1:2). The results showed that the CN/LFCO(1:2) reached 85.2% MNZ degradation within 150 min, and the apparent rate constant was 0.01230 min −1 , which was 2.82 times higher than that of LFO (0.00436 min −1 ). The active species trapping experiments showed that ·OH and h + were the main active species; therefore, a Z-scheme charge transfer, interfacial electron cycle of Cu + /Cu 2+ and Fe 2+ /Fe 3+ , and oxygen-defective synergistic catalytic mechanism were proposed. It is believed that the CN/LFCO (1:2) catalyst has great application prospects in environmental remediation. Graphical abstract