Synthesis And Visible-light Photocatalytic Performance Of Bismuth-tungsten Oxide Materials

With the rapid development of industrialization and the continuous improvement of people’s quality of life,the problem of environmental pollution and even the damage of ecological system has become more and more serious.Air and water,in particular,are indispensable substances directly related to human life.Air pollution and water pollution directly harm human health,leading to a series of chronic diseases with chronic diseases and long-term effects.The problem of air pollution and water pollution urgently needs to find a kind of low cost,high efficiency,green environmental protection technology to solve.Therefore,photocatalytic technology has become the main degradation technology for dyestuff wastewater treatment due to its unique advantages in the degradation of dyestuff wastewater.The different morphology and structure of photocatalysts are one of the important reasons for their different catalytic effects,Preparation and study of photocatalysts with different morphological structures have become one of the important research directions.However,Bi_3.84W_0.16O_6.24 photocatalyst could not achieve the desired catalytic performance due to its wide band gap.Therefore,loading the surface of the catalyst with noble metal is one of the effective means to reduce the band gap and improve the separation rate of photogenic carriers so as to improve the photocatalytic efficiency.As a precious metal,Ag can rapidly capture photogenerated electrons on the surface of Bi_3.84W_0.16O_6.24 which effectively inhibits photogenerated e-and h+recombination,and thereby improve the photocatalytic performance of Bi_3.84W_0.16O_6.24.The research and synthesis of structurally specific Ag/Bi_3.84W_0.16O_6.24 composite materials to improve photocatalytic performance has gradually become a hot research direction.The experimental research contents of Bi_3.84W_0.16O_6.24 and Ag/Bi_3.84W_0.16O_6.24 composite materials in this paper are as follows:（1）The anhydrous methanol and water were used as the reaction solvent,Bi（NO₃）₃.5H₂O and Na₂WO₄.2H₂O were used as reactants,and Bi_3.84W_0.16O_6.24 was synthesized by a simple one-step solvothermal reaction.A series of Bi_3.84W_0.16O_6.24 samples were synthesized by changing the solvent ratio.XRD,BET,FESEM,HRTEM,uv-vis and other methods were used to characterize the structure and performance of the samples.Methylene blue was selected as the target pollutant for photocatalytic degradation under the simulated visible light condition to test the photocatalytic performance of the synthesized Bi_3.84W_0.16O_6.24 sample,and its cyclic stability was tested.The results show that when the ratio of anhydrous methanol to water is 1:5,the synthesized flower-like Bi_3.84W_0.16O_6.24 has higher degradation efficiency.（2）The spherical Ag/Bi_3.84W_0.16O_6.24 composite was synthesized by secondary solvent thermal reaction.A series of Ag/Bi_3.84W_0.16O_6.24 composite materials with different content ratios were synthesized by loading different amounts of Ag on precursor Bi_3.84W_0.16O_6.24,and various characterization and photocatalytic performance tests were carried out.The results show that the degradation efficiency of methylene blue（MB）is the highest in 3%-Ag/Bi_3.84W_0.16O_6.24 composite under visible light irradiation.（3）The hollow microsphere Ag/Bi_3.84W_0.16O_6.24 composite was synthesized by a simple one-step solvothermal method.The optimal addition amount of Ag was explored by changing the addition amount of AgNO₃ in the reaction substrate,and the samples synthesized by different addition amounts of Ag were evaluated by various characterization methods and photodegradation tests.The results showed that when the mass ratio of Ag was 3%,the prepared hollow microsphere 3%-Ag/Bi_3.84W_0.16O_6.24 composite had excellent photocatalytic performance.At the same time,the groups that might play a role in the degradation process of the composite were investigated,and the cyclic stability of the sample was tested.