Application of Zn1−xCdxS Photocatalyst for Degradation of 2-CP and TC, Catalytic Mechanism

Abstract

Zn1−xCdxS catalysts with Zeolitic Imidazolate Framework-8 (ZIF-8) as the precursor were successfully prepared by ion exchange method, and the ability and electrochemical properties of a series of ZIF-8, ZnS and Zn1−xCdxS catalysts in photocatalytic degradation of 2-CP and TC were investigated. Doping of Cd ions was able to modulate the ZnS band gap width and improve the utilization of visible light by the photocatalyst. The nanocage catalysts with hollow structure of Zn1−xCdxS have better photocatalytic response. The removal of photocatalytic pollutants was up to 90% under optimal conditions. Using a Peroxymonosulfate (PMS)-assisted system to improve the degradation efficiency of 2-chlorophenol and tetracycline hydrochloride under visible light, we present a possible mechanism of Zn1−xCdxS as a photocatalyst for degradation in persistent pollutants and in PMS-assisted photocatalysis. Four active species, O2−, h+, -OH, and SO4•−, can be generated to degrade 2-chlorophenol and tetracycline hydrochloride under PMS-assisted activation. Zn1−xCdxS nanocage with high activity and stability provides a feasible approach to catalytically remove persistent pollutants from aqueous solutions under visible light conditions.