A photocatalyst combined of copper doped ZnO and graphdiyne (Cu/ZnO@GDY) for photocatalytic degradation of tetracycline: Mechanism and application

Abstract

Photocatalytic membrane reactor (PMR) is receiving increasing attention in purification of antibiotic contaminated water bodies, but its development is limited by the lack of efficient photocatalyst that can be well integrated with the membrane. In this study, a photocatalyst combined of copper doped ZnO and graphdiyne (Cu/ZnO@GDY) was synthesized to address this challenge. Cu/ZnO@GDY exhibited excellent degradation ability towards tetracycline hydrochloride (TC), owing to the synergistic effect of •O₂^- and h⁺. The DFT calculation results indicated that copper doping effectively optimized the band structure of ZnO, and the combining of graphdiyne further enhanced the separation efficiency of photogenerated carriers which was attributed to the formation of a S-scheme heterojunction. Furthermore, we explored the integration of Cu/ZnO@GDY with the polyethersulfone (PES) membrane in PMR. Notably, in a 10 mg/L TC solution, the removal efficiency remained stable at around 80% at 25 °C, 250 mW·cm^-2, and 15 L·m^-2·h^-1. This work provides a reference for the practical application of the photocatalytic degradation of antibiotics.