Construction of a Double Z‐Scheme CuO/Cu2O/CuS/ZnO Quaternary Heterojunction Photocatalyst with Enhanced Solar‐Driven Photocatalytic Performance for Sulfamethoxazole Degradation

Abstract A novel CuO/Cu 2 O/CuS/ZnO quaternary heterojunction photocatalyst was constructed through a facile microwave technique. The structure, morphology and optical properties were characterized and explored. The photocatalytic activity of CuO/Cu 2 O/CuS/ZnO quaternary composite was assessed by antibiotic sulfamethoxazole under the simulated solar light irradiation. The quaternary composite manifested more excellent photocatalytic performance than the pristine ZnS and CuO/Cu 2 O. Moreover, the effects of ascorbic acid concentration on removal efficiency of sulfamethoxazole were discussed, revealing the importance of Cu 2 O in sulfamethoxazole removal. Particularly, as the ascorbic acid was 0.50 M, the total removal efficiency of sulfamethoxazole at an initial concentration of 20 mg/L was approximately 99.17 %, and the fitted pseudo‐first‐order kinetic rate constant reached 0.0380/min, which were 1.73 and 6.91 times of that in the absence of ascorbic acid, respectively. A double Z‐scheme charge transfer mechanism was confirmed by the reactive species trapping tests, which demonstrated that superoxide radicals and holes were the major reactive species responsible for sulfamethoxazol degradation. CuO/Cu 2 O/CuS/ZnO nanocomposite provided an interesting perspective for a highly efficient quaternary photocatalyst that could be employed for remediation antibiotics.