MOF derived rod-shaped Fe-ZnO/CdS Z-type heterostructure with efficient photocatalytic degradation of ciprofloxacin

The continuous contamination of ciprofloxacin (CIP) pharmaceutical residues poses a potential risk to the ecological environment and human health. Using semiconductor materials with optimized heterojunctions for photodegradation is an effective way for the CIP removal. In this study, Fe-ZnO/CdS Z-type heterojunction was synthesized, and used for the photodegradation of organic pollutants. The Fe-doping brought abundant surface oxygen vacancies to ZnO, which could effectively promote interfacial electron transfer. In addition, the valence transition of Fe (II)/Fe (III) could effectively participate in the redox cycle and improve the carrier transfer efficiency. The construction of Z-type heterojunction facilitated the separation of photogenerated carriers, and the photogenerated electrons in the conduction band of CdS reduced oxygen to produce superoxide radicals as the main active radicals. A series of photoelectric characterizations had proved that the introduction of CdS could effectively improve the visible light utilization rate and photogenerated carrier separation efficiency. The Fe-ZnO/CdS system achieved 90.0% degradation efficiency of CIP within 120 min under visible light. Impressively, Fe-ZnO/CdS heterojunction showed practical degradation capability in complex aqueous environments and excellent reusability. This study provided an effective strategy for the design of metal oxide-based photocatalysts and offered a new idea for the removal of drug residual contaminants.