Bandgap-Tunable ZnxCd1−xS Solid Solutions for Effective Photocatalytic Degradation of Norfloxacin Under Visible Light and Natural Sunlight

Due to its broad-spectrum antibacterial activity, norfloxacin (NOR) has been widely used over the past few decades. However, the residual NOR in aquatic ecosystems could pose risks to human health from bacteria with resistance genes that potentially cause serious infectious diseases. Herein, a series of bandgap-tunable ZnxCd1−xS (x = 0~1) solid solutions were hydrothermally synthesized and used for NOR photodegradation under visible light and natural sunlight. Benefitting from the suitable bandgap, band structure, and unique tetrapod shape nanostructure, the Zn0.1Cd0.9S solid solution exhibited the best photocatalytic activity, with high degradation efficiencies of 83.23% and 86.28% under visible light and natural sunlight, respectively, within 60 min, which is remarkable among reported ZnxCd1−xS-based photocatalysts and other materials. The in situ reactive-species trapping experiment revealed that holes (h+) were the primary species, and a possible photodegradation mechanism was thus suggested. Moreover, Zn0.1Cd0.9S also exhibited decent reusability and stability after five cycles of experiments. This work provides a comprehensive exploration of the application of bandgap-tunable ZnxCd1−xS solid solutions for NOR photodegradation under visible light and natural sunlight, demonstrating the promising application of as-synthesized Zn0.1Cd0.9S in the photocatalytic degradation of antibiotics.