Preparation Of Bismuth-base And Supported Catalysts And Their Performances For Photocatalytic Organic Synthesis

For a long time,Environmental pollution problems and energy crisis issues are two major problems that have always affected human survival.Among them,semiconductor photocatalysis,as an effective method with the characteristics of converting solar energy into chemical energy,has received extensive attention,which are widely used in the field of organic pollution degradation,water decomposition and organic synthesis.In this paper,the application of photocatalysts in the field of organic synthesis are studied.Bi₂WO₆ and Bi₄Ti₃O₁₂2 have been selected as research objects because of their high photocatalytic activity and stability.A series of different types of Bi₂WO₆,different contents of Bi₄Ti₃O₁₂/Bi₂WO₆ and Au/Bi₄Ti₃O₁₂2 catalysts were prepared by hydrothermal method,ultrasonic method and NaBH₄ reduction method by using Bi₂WO₆ and Bi₄Ti₃O₁₂semiconductors,the morphology,structure and valence state of the catalyst were characterized by powder X-ray diffraction?XRD?and other characterization methods.The SEM results showed that Bi₂WO₆?nitric acid method,pH=4 to 5,130°C?was a flower-like microsphere structure assembled from narrow nanosheets with good performance,60%Bi₄Ti₃O₁₂/Bi₂WO₆ was evenly arranged in layers,4%Au/Bi₄Ti₃O₁₂2 had a layered spherical structure filled with nanosheets.UV-vis DRS and PL characterization showed that both of them had an absorption in the visible light region and could effectively inhibit the recombination of photogenerated charges and holes.These demonstrated the excellent performance of the catalyst.Further,Bi₂WO₆,Bi₄Ti₃O₁₂/Bi₂WO₆ and Au/Bi₄Ti₃O₁₂2 were respectively applied to the alpha alkylation and amination reactions,and the data showed that:Bi₂WO₆ prepared by the nitric acid method?pH=4 to 5,130°C?,the two-phase composite ratio was 60%of Bi₄Ti₃O₁₂/Bi₂WO₆,and the Au loading was 4%of Au/Bi₄Ti₃O₁₂2 catalyst,had the highest catalytic activity.Optimize results by optimizing multiple variables,and under the optimal conditions,the effects of alcohols,ketones and amine derivatives on the reaction were also studied,and other factors that might affect the reaction were also explored.For example:wavelength and light intensity.finally,the catalysts were tested for cycling ability and active species.