Preparation And Properties Of Multifunctional Bi₂S₃@Ag₂S/CC Photocatalysts

With the rapid development of the medical industry,the use of antibiotics is also increasing,leading various organic pollutants to flow into the environment and endanger human health.Therefore,the removal of tetracycline antibiotics in the environment is an urgent research topic at present.Semiconductor photocatalysts,as a new and environmentally friendly material,have been widely used in photocatalytic technology in recent years,and different material systems have been developed.However,most semiconductor photocatalysts are powdered materials.The practical application of powdery materials is hindered because of its disadvantages such as difficulty in recycling,secondary pollution and insufficient utilization of sunlight.The researchers find that the main way to solve these problems is to load photocatalysts on low-density lightweight materials.Photothermal catalysts at the gas-liquid interface can absorb sunlight more fully,thus generating more photoexcited electron hole pairs and heat.Therefore,a kind of carbon fiber cloth load with Bi₂S₃@Ag₂S heterojunction is successfully prepared by hydrothermal in-situ growth method combin with ultrasound-assisted strategy.The catalyst can not only float on the water surface,but also degrade a variety of pollutants in low temperature water.The paper focuses on the following contents:（1）Bi₂S₃ nanospheres are prepared by hydrothermal method,and then Ag₂S is uniformly coated on the surface of Bi₂S₃ by in-situ growth method.The Bi₂S₃@Ag₂S heterostructures with 3D nanocrystalline core-shell structure are obtained.The crystal phase structure,element morphology and morphology characteristics of the prepared samples are studied by common characterization methods.Using tetracycline as the main pollutant,by adjusting different influencing factors,it is determined that when the p H value is 7,the pollutant concentration is 10 mg/L,and the dosage of Bi₂S₃@Ag₂S is 50 mg,the best photocatalytic degradation effect of the pollutants can be achieved.The successful preparation of Bi₂S₃@Ag₂S heterojunction not only enhances the photoresponse range of the original photocatalyst,but also helps to improve the photocatalytic and photothermal properties.Bi₂S₃@Ag₂S nanoheterojunctions are subjected to free radical quenching experiments,and the main active factors in the photocatalytic process are explored.The experimental results show that the heterojunction show good photocatalytic activity against various pollutants.The formation of heterojunction not only improve the photocatalytic efficiency of the original catalyst,but also enhance the stability of the photocatalyst.（2）The Bi₂S₃@Ag₂S is successfully loaded on the surface of the carbon cloth using the ultrasonic-assisted method,and a self-floating photocatalyst with broad spectral response is prepared.The crystal phase structure,element morphology,surface heating rate,photoelectric characteristics and morphological characteristics of the prepared samples are studied by common characterization methods.Taking tetracycline as the main pollutant,the change of photocatalytic efficiency is studied by changing the type of catalyst,the concentration of the initial pollutant and the light intensity.The self-floating carbon fiber cloth as the base material not only absorb the sunlight convert into heat energy,but also facilitate the recycling of the catalyst.Finally,the degradation principle of the self-floating nano Bi₂S₃@Ag₂S/CC（Carbon fiber cloth）photocatalyst are explored.The superoxide free radical and oxygen vacancy are determined to be the main active substances in the catalyst.