Preparation Of MnS/BiVO₄ With Pn Heterojunction Flower-like Microspheres And Its Visible Light Photocatalytic Performance

The increasing prosperity of the industrialization process has caused more and more prominent problems.However,the water as the source of life has the most serious impact on humans and the environment.Industrial wastewater and biomedical wastewater account for the vast majority.Traditional wastewater treatment technology has been relatively weak.Therefore,photocatalytic environmental remediation technology has emerged as the new generation of wastewater treatment technology with the most potential.As an excellent photocatalyst under visible light response,bismuth vanadate has many excellent properties such as chemical stability,non-toxicity,cheap raw materials and high light absorption performance,which attracted a lot of attention.However,a single semiconductor cannot bypass the problem of easy combination of photogenerated electrons and holes.Therefore,in order to solve the above problems,in this paper,a flower-like microsphere Mn S/BiVO₄ composite photocatalyst with p-n heterojunction was successfully prepared,which improved the adsorption capacity and degradation capacity of pollutants.The details are as follows:(1)BiVO₄with different pH was prepared by a simple hydrothermal method,and characterized by XRD,SEM,UV-VIS and other means.Among them,BiVO₄ with p H=12 has excellent performance and was selected for the next work.Due to BiVO₄has a uniform morphology and a large structural specific surface area at p H=12,it can be easily combined with other types of semiconductors,providing more active sites,and adsorbing a large number of reactants to cause a photocatalytic reaction.In addition,BiVO₄with p H=12 has the largest light absorption range,which makes the utilization rate of light and the efficiency in the reaction was improved.(2)The photocatalysts with p-n heterojunction flower-like microspheres Mn S/BiVO₄ in different proportions were successfully prepared by hydrothermal and annealing methods to improve the photocatalytic performance.Using XRD,SEM,XPS,UV-Vis DRS and other characterization techniques to conduct detailed research on the material structure and photoelectric properties of a series of synthesized p-n heterojunction samples,and provide theoretical support for the subsequent inference of the photocatalytic mechanism.Under the irradiation of visible light,M3B2 has excellent separation efficiency of photogenerated electrons and holes.On account of the composite material forms a p-n heterojunction,which expanded the light absorption performance,generated an internal electric field on the surface of the material,and accelerated the photogenerated current.The flow of electrons extended the life of free electrons,thereby enhancing the photocatalytic performance of the composite material.(3)In this paper,The photocatalysts with p-n heterojunction flower-like microspheres Mn S/BiVO₄ were successfully designed and prepared and applied it to the degradation of organic pollutants in water.The M3B2 composite material showed the best excellent photocatalytic performance.This material has a strong degradation effect not only for dye-based MB aqueous solutions,but also for antibiotics CIP and TC aqueous solutions.Finally,the degradation mechanism of this p-n heterojunction photocatalyst was simply conceived and proposed,and the work of degrading organic pollutants in water was theoretically summarized.