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 1000 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 center dot OH, h(+), and center dot O-2(-) 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.