Study On Preparation Of Bismuth Molybdate-sulphide Composite Catalyst And Its Photocatalytic Performance

At present,there are still a variety of problems in the field of photocatalysis,such as the limited types of catalysts,the need to use ultraviolet light or toxic solvents,and the low catalytic efficiency,which must be overcome.Bi₂MoO₆ has become one of the most researched photocalytic materials with excellent properties such as moderate valence band position,environmental protection and good optical performance.To some extent,it exhibits photocatalytic performance towards the degradation of pollutants.However,the small specific surface area of single Bi₂MoO₆ and the high recombination of the electron-hole pair are not conducive to its excellent photocatalytic activity.These are the main reasons that limit its wide application.So far,semiconductor composites based on Bi₂MoO₆ are mainly used to promote the photocatalytic performance towards the degradation of pollutants under the condition of visible light.At the same time,XRD,SEM,EDS,BET and other characterization means were performed to analyze the morphology,composition and microstructure of the as-prepared samples.The main contents of this paper are as follows:Bismuth nitrate pentahydrate was used as the source of bismuth,and three Bi₂MoO₆ semiconductor materials with different morphologies are prepared by solvothermal and hydrothermal methods.The as-obtained three Bi₂MoO₆ materials are characterized by XRD,SEM,EDS,BET and other characterization methods,and theirs morphology,composition and microstructure were analyzed.In order to further explore the effect of theris morphology on the photocatalysis,the photocatalytic degradation towards Rhodamine B is tested on the the as-synthesized Bi₂MoO₆ semiconductor materials.Among them,the core-shell-like Bi₂MoO₆ material with the largest specific area exhibits the best photoatalytic performance,and the degradation rate of Rhodamine B under simulated sunlight irradiation in 90 min can reach 84%.The above mentioned Bi₂MoO₆ samples with different morphologies were used as substrates,and the Bi₂MoO₆/ZnS composites with the similar morphology to the substrate are successfully synthesized by the hydrothermal method.XRD,SEM,EDS,BET and other characterization tests are performed and the morphology,composition,and microstructure of the composite materials are analyzed based on the characterization results.Then the photocatalytic activities of the three Bi₂MoO₆/ZnS samples are compared with that of the corresponding single Bi₂MoO₆ semiconductor materials.It is concluded that the specific surface area of the Bi₂MoO₆ semiconductor material is greatly improved compared to that of a single Bi₂MoO₆ semiconductor material.Among them,the Bi₂MoO₆/ZnS composite material with the core-shell-like structure exhibits the best photocatalytic performance.The photocatalytic degradation rate towards Rhodamine B is 99.6%within 45 min.Similarly,using three single Bi₂MoO₆ samples as substrates,the Bi₂MoO₆/CdS composites with the similar morphology to the substrate are successfully synthesized byThe hydrothermal method.XRD,SEM,EDS,BET and other characterization tests are performed,and the morphology,composition,and microstructure of the composite materials are analyzed according to the characterization results.Then the photocatalytic activities of three Bi₂MoO₆/CdS samples are compared with that of the corresponding single Bi₂MoO₆ semiconductor materials.Therefore,it is concluded that the specific surface area of any composite is much larger than that of a single Bi₂MoO₆semiconductor material.Among them,the Bi₂MoO₆/CdS composite material with a hollow-like morphology exhibits the best photocatalytic performance under simulated sunlight irradiation.The photocatalytic degradation rate towards Rhodamine B within45 min 99.3%.