The Preparation And Photocatalytic Performance Of BiF₃-based Composite Materials

With the rapid development of human society,various technologies are becoming more and more advanced,the economy is becoming more prosperous,and the explosive growth of the population has also brought serious problems such as the rapid consumption of energy and the destruction of the environment.The reserves of fossil energy available for mining are decreasing year by year,and human beings have virtually caused inestimable damage to the environment in order to meet daily survival needs.This forces humans to find an alternative green new energy source.Under this background,the development and application of photocatalysis technology has provided new ideas for solving the problems of environmental pollution and energy shortage,and has become a hot research topic at home and abroad.TiO₂ is a common semiconductor photocatalytic material.In addition,bismuth-based semiconductor photocatalysts have also been found to have good photocatalytic activity,can effectively degrade pollutants,and have considerable development prospects.In this paper,bismuth fluoride,a newly discovered material,is used as the main research object,and bismuth fluoride-based composites are prepared by microwave heating and solvothermal methods.Most bismuth-based semiconductor photocatalysts can be excited by visible light and have visible light catalytic activity.Although bismuth fluoride is also a kind of bismuth-based semiconductor photocatalytic material,it exhibits ultraviolet photocatalytic performance,and it has the problem of easy recombination of photogenerated electrons and holes,making it difficult for bismuth fluoride to be used alone as a photocatalyst materials.Therefore,some methods must be adopted to solve the limitations of the bismuth fluoride material,so that it also responds to visible light,improve the utilization of sunlight,and thus improve the photocatalytic activity.Heterojunction formation using semiconductor recombination is one of the effective ways to improve the separation of photogenerated electron-hole pairs.In this paper,a p-type semiconductor BiOI and an n-type semiconductor BiF₃ were used to obtain a BiOI/BiF₃ heterojunction structure.Based on this structure,further research is carried out to modify semiconductor materials and increase oxygen vacancies.The structure and morphology of materials were characterized and analyzed by means of X-ray diffraction,photoelectricity,diffuse reflection of ultraviolet-visible light,scanning electron microscope,transmission electron microscope,and fluorescence.The specific research content is as follows:?1?The bismuth source was provided by bismuth nitrate pentahydrate,the iodine source was provided by potassium iodide,the fluorine source was provided by sodium fluoride,and glacial acetic acid was used as a solvent.Rapid synthesis of BiOI/BiF₃composite photocatalyst by microwave-assisted synthesis.Then a series of characterization methods were used to explore its possible photocatalytic reaction mechanism.The results show that the photocatalytic degradation activity of BiOI/BiF₃composite is higher than that of pure bismuth fluoride under simulated sunlight,and the1:3 composite material exhibits the best photocatalytic activity.?2?A series of OV-BiOI/BiF₃ composites containing oxygen vacancies were synthesized using microwave-assisted methods using methanol and ethylene glycol as the main solvents.Then,the performance test of photocatalytic degradation of tetracycline hydrochloride was carried out,and the possible reaction mechanism was discussed.The results show that under simulated sunlight,OV-BiOI/BiF₃ composites have more ideal photocatalytic activity than composites without oxygen vacancies,and still show the highest photocatalytic activity when the sample ratio is 1:3.