Preparation And Catalytic Performance Of MoS₂/BiVO₄ Composite Photocatalyst

As a photocatalytic material with low toxicity,chemical stability,environmental friendliness and high utilization rate of sunlight,bismuth vanadate has attracted more and more attention from scholars at home and abroad.However,the photocatalytic carrier of yttrium vanadate is easy to compound and its application is limited.Therefore,the modification of bismuth vanadate catalyst has become a hot research topic in recent years.Semiconductor compounding is one of the effective methods to promote the effective separation of bismuth vanadate and improve the photocatalytic performance in the modification of bismuth vanadate.In this paper,a solvothermal method was used to prepare pure phase monoclinic phase bismuth vanadate photocatalyst with lanthanum nitrate pentahydrate as the source of vanadium as well as vanadic acid amine as vanadium source and nitric acid and ammonia as solvent.Bismuth vanadate mixed with tetragonal phase and monoclinic phase was prepared by traditional solvothermal method The molybdenum disulfide monomer was prepared by hydrothermal method with ammonium heptamolybdate as the ammonium source and thioacetamide as the sulfur source.The in-situ synthesis method was successfully combined with the monoclinic phase bismuth vanadate.The various catalysts prepared were characterized by XRD,SEM,PL,BET.The catalytic performance of the catalyst was studied by UV-Vis and photocatalytic experiments.The optimum doping amount of molybdenum disulfide was determined and the photocatalytic reaction mechanism was discussed.Finally,Rhodamine B was used as the target treatment,and photocatalytic experiments were carried out to explore the optimal treatment conditions and the recycling effect of the catalyst.?1?The optimum conditions for the preparation of monoclinic phase bismuth vanadate with solvothermal method were discussed.Monoclinic phase bismuth vanadate is micrometer-sized microspheres?flower spheres?.The monoclinic phase bismuth vanadate prepared under the optimal conditions has a large difference in the crystal form of vanadic acid prepared by the traditional solvent method.The monoclinic phase of vanadate vanadate has more regular morphology and specific surface area.It is larger and therefore has better catalytic performance.?2?The optimal conditions for the preparation of MoS₂/BiVO₄ composite photocatalyst by solvothermal method were discussed.The composite of MoS₂ and BiVO₄ increased the specific surface area of the composite photocatalyst,which caused a red shift in the absorption band of light and increased the visible light.?3?The forbidden band width of each of molybdenum disulfide,bismuth vanadate and composite photocatalyst was determined by UV-Vis spectrum analysis;The valence band and conduction band position of molybdenum disulfide and bismuth vanadate are calculated by the formula.The photocatalytic mechanism results show that the main active species in the photocatalytic reaction of the composite photocatalyst is cavity.Therefore,the structure of the composite photocatalyst was judged to be a p-n heterojunction between molybdenum disulfide and bismuth vanadate.?4?The optimum conditions for photocatalytic treatment of rhodamine B by composite photocatalyst were studied.Under the optimal treatment conditions,the maximum chroma removal rate of rhodamine B was 76.65%,and the maximum COD removal rate was 53.01% respectively.And through the recovery experiment,it is proved that the prepared composite catalyst has higher recycling value.