One-pot construction of S–Mo co-doped BiOCl toward simultaneously decreasing size,tuning energy band structure,and promoting charge separation for efficient photocatalytic degradation of organic pollutants

Bismuth oxychloride (BiOCl), although it has exhibited intensely potential used in photocatalyst for environmental remediation, owns wide bandgap and the fast photocharge recombination that limits its effective application. Doping BiOCl used in metal and non-metal elements simultaneously, as a feasible strategy in designing novel visible-light photocatalysts, was conductive to effectively overcome the as-above defects. The present work constructed S-Mo co-doped BiOCl-- with abundant reactive sites via one-pot hydrothermal method. The as-prepared S–Mo co-doped BiOCl sample presents the best-visible light-driven photodegradation performance, and its kinetic constant (k) is about 16.8 times (for rhodamine B) and 6.5 times (for tetracycline hydrochloride) higher than that of pure BiOCl, respectively. By contrast, S-Mo co-dopant induced the decrease of nanosheets size and endowed the large specific surface areas, which favors the increased reactive sites. Further analysis with the aid of experiments and density function theory calculations indicated that the intermediate level induced by S 2p orbitals could narrow the bandgap and promote the excitation of electron from conduction band to valance band via providing the middle springboard on the one hand, and the Mo energy states was conducive to promote the separation of charge carriers by acted as the acceptor for the photoinduced electrons on the other hand. Consequently, the potential origin of the improved visible-light-driven performance lies in the more superoxide radicals for oxidizing organic pollutants caused by the simultaneous enhancement of visible light absorption as well as charge separation resulted from the further optimization of energy band structure that associated with the doping energy level of S-Mo co-doping in BiOCl. This work demonstrated that S and Mo co-doping BiOCl is of highly promising candidate for the further progress of environmental remediation.