The facile fabrication of novel visible-light-driven Z-scheme CuInS2/Bi2WO6 heterojunction with intimate interface contact by in situ hydrothermal growth strategy for extraordinary photocatalytic performance

The pollution of pharmaceutical wastewater has attracted global attention. Photocatalysis is an attractive yet challenging method for the degradation of pharmaceutical residues. Fabricating efficient Z-scheme heterojunctions with intimate interface contact for enhancing the performance of photocatalysts is a challenge. Herein, novel visible-light-driven direct Z-scheme CuInS2/Bi2WO6 heterojunctions with intimate interface contact were successfully synthesized by in situ hydrothermal growth of Bi2WO6 directly on the surface of CuInS2 network-like microspheres, and the content of CuInS2 was optimized. The photocatalytic activity of optimal Z-scheme 15% CuInS2/Bi2WO6 for the degradation of tetracycline hydrochloride (TC•HCl) is more than three times that of bare CuInS2 and 17% higher than that of Bi2WO6, which is attributed that the intimate interface contact can assure excellent interfacial charge transfer abilities. Moreover, Z-scheme CuInS2/Bi2WO6 heterojunctions are highly stable with no inactivation in photocatalytic cycles. More importantly, real pharmaceutical industry wastewater can be efficiently disposed by Fenton-aided photocatalysis of Z-scheme CuInS2/Bi2WO6 heterojunctions with COD removal efficiency being 90.5%, which is much higher than the reported results, and thus sets a new performance benchmark for practical application in real pharmaceutical wastewater treatment.