Synergistic Mechanism of ZnCr-LDHs/C‑g‑C3N4 Photocatalyst for Efficient Degradation of Antibiotics under Visible Light

With the widespread use of antibiotics, water pollution and biological systems have become serious. There exist many challenges for their degradation, and the key to photocatalytic degradation is the rational design of photocatalysts and a thorough understanding of their catalytic mechanism. In this paper, tetraphenylphosphorus chloride as a carbon source was doped into g-C3N4, and a C doping g-C3N4 photocatalyst (C–CN-550) was prepared with rich porosity, high surface area, and expanded delocalization of π-electrons. When ZnCr-LDHs were in situ formed on the C–CN-550 substrate, we constructed an efficient photocatalyst ZnCr-LDHs/C–CN-550 with highly dispersed LDHs, synergy of π-electrons, defects, interfaces, and fully exposed active sites on the surface. Ciprofloxacin and tetracycline hydrochloride (10 ppm) can be completely degraded within 30 min by the ZnCr-LDHs/C–CN-550 catalyst under visible light irradiation. Further, the synergistic mechanism was revealed through various characterizations, which provides new ideas and strategies for the construction of composite photocatalysts.