Z-Scheme BiOCl-Au-CdS Heterostructure with Enhanced Sunlight-Driven Photocatalytic Activity in Degrading Water Dyes and Antibiotics

Although semiconductor photocatalysis has made great progresses as a promising solution to solve the problem of environmental pollution, the highly efficient decomposition of organic pollutants driven by sunlight is still a challenge. Herein, we successfully constructed a Z-scheme photocatalyst BiOCl-Au-CdS for the first time by stepwise deposition of Au and CdS. It was found that the Au nanoparticles (NPs) were selectively anchored on the {001} facets of BiOCl nanosheets in the process of photoreduction while CdS NPs were further in situ deposited on Au NPs via the strong S–Au interaction. Compared to BiOCl, BiOCl-Au, and BiOCl-CdS, the Z-scheme BiOCl-Au-CdS exhibited evidently higher sunlight-driven photocatalytic activity toward the degradations of anionic dye Methyl Orange, cationic dye Rhodamine B, colorless pollutant phenol, and antibiotic sulfadiazine. The radical trapping experiments indicated that ·OH, h+, and ·O2– are the main reactive species responsible for the degradations of organic pollutants over BiOCl-Au-CdS. Based on the photoelectrochemical measurements, PL spectra, and band potential calculation, it can be concluded that the Z-scheme structure of BiOCl-Au-CdS not only retains the photogenerated electrons and holes with higher redox ability but also decreases their recombination rate. As a highly efficient sunlight driven photocatalyst, BiOCl-Au-CdS can be potentially used in environmental pollutant remediation.