| Recently,photocatalysis technology based on semiconductor materials is considered to be a practical environmental purification treatment method.Aiming at the problems of poor light absorption and fast electron-hole recombination rate faced by existing photocatalysts,this paper takes advantage of the unique physical and chemical properties of metal sulfide semiconductors to develope a series of novel sulfide-based photocatalysts for removal of pollutants in the environment.We investigate the photocatalytic activity of metal sulfide-based composite on environmental pollutants,combined with the analysis of the intrinsic structure and photoelectric properties of photocatalytic materials,the relationship between the structure,properties and performance of the catalyst is finally explained.First,the preparation of Mo S2 with controllable morphology was achieved through a mild hydrothermal process.The photocatalytic activity of the prepared samples was evaluated by catalytic reduction of Cr(VI),and the relationship between photocatalyst morphology and photocatalytic activity was further studied.In order to alleviate the severe recombination of photogenerated electron/hole pairs in the monomer Mo S2 photocatalyst,the Sr Mo O4/Mo S2 composite material was prepared by a one-step hydrothermal method.XPS and Raman analysis confirmed that strong interface effect is exsisting between the bulk Sr Mo O4 and Mo S2 nanosheets in the8%-Sr Mo O4/Mo S2 composite.At the same time,the 8%-Sr Mo O4/Mo S2 photocatalyst shows the best Cr(VI)removal rate(91.2%),and has good light stability under visible light irradiation.At the same time,via the in-situ coupling of S defects on the surface of Mo S2nanosheets and L-cysteine,the superlattice Cu2S nanoparticles(average 6.2 nm)are uniformly dispersed on the Mo S2 nanosheets.XPS and Raman analysis confirmed the formation of a strong interface effect between Cu2S and Mo S2 in the 2-Cu2S-Mo S2composite,which greatly promoted the separation of photogenerated electron/hole pairs and prolonged their life.Finally,2-Cu2S-Mo S2 exhibits the fastest Cr(VI)photoreduction rate under visible light irradiation,which is about 8.3 times and 2.9times that of Mo S2 nanosheets and pure Cu2S.This strategy has been extended to the preparation of Cd S-Mo S2 and Zn S-Mo S2 heterojunctions.This strategy has broad prospects in the design of more active metal sulfide heterojunction photocatalysts.In addition,a cell-like Zn S/Zn O composite was synthesized by a one-step hydrothermal method.Compared with pure Zn S and Zn O,the Zn S/Zn O composite has greatly improved catalytic degradation activity of tetracycline(TC)under visible light.Cycling experiments also show that Zn S/Zn O composite materials have good light stability and good photocatalytic activity.The Bi2S3/Cd S heterojunction was also successfully constructed by the in-situ ion exchange method,in which a strong interaction was formed between Bi2S3 and Cd S,which made the heterojunction with efficient carrier migration efficiency and long carrier lifetime.The photocatalytic results show that the Bi2S3/Cd S heterojunction not only exhibits strong photoreduction activity,but also has the best photooxidation ability.Through the study of photocatalytic mechanism,the S-type photoreaction mechanism reveals the efficient carrier transfer efficiency of Bi2S3/Cd S heterojunction and its strong redox ability. |
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