Preparation Of Bismuth Photocatalyst And Its Performances For Catalytic Organic Synthesis Reactions Under Visible Light

As fossil energy is decreasing,solar energy?as a clean and pollution-free energy source?has been used by us.Improving the utilization of solar energy is an important issue that we need to solve now.Scientists have studied a series of methods to convert solar energy into chemical energy and improve the utilization of solar energy.Among them,semiconductor photocatalysis is one of the efficient and low energy consumption methods.Major break throughs have been made in the use of solar energy to synthesize organics,degrade pollutants,and produce self-cleaning materials,etc.Bi-based compounds are notable for their unique crystal structure and suitably sized forbidden band width,bismuth catalyst of Bi₂MoO₆ and BiVO₄ in photocatalytic activity and good stability as the research object of most people.The preparation of different crystal structure and morphology of Bi₂MoO₆ and BiVO₄ in this paper,such as light catalyst structure,morphology and optical properties of a series of characterization results by XRD,UV-vis DRS,SEM,TEM,XPS,BET and PL.The experiment is divided into two parts.In the first part of the experiment,a series of flakes of?-Bi₂MoO₆ with different thicknesses were prepared by hydrothermal synthesis.During the preparation process,changing the type of solvent,pH value,and hydrothermal temperature will make?-Bi₂MoO₆ The thickness changes,which in turn changes the photocatalyst activity,Then use NaBH₄ reduction method to prepare Pt/?-Bi₂Mo₆ supported photocatalysts with different mass fractions,and apply the prepared Pt/?-Bi₂Mo₆ photocatalysts to the aldol condensation reaction of benzyl alcohol and acetophenone.4 wt%of Pt/?-Bi₂Mo₆?nitric acid solvent,pH=9,180??is the optimal catalyst,using a single variable to optimize the reaction conditions,such as the type of solvent,alkali,alkali,the amount of reactants,etc.The conversion rate of the aldol condensation reaction of methanol and acetophenone reached the highest,the conversion rate of the reaction reached 80.7%,and the effect of wavelength and light intensity on the reaction was explored,and then the alcohol and ketone derivatives were investigated.At the end of the experiment,the stability of the catalyst was tested.The experimental results show that the catalyst can still maintain a high activity after five cycles;the second part of the experiment successfully prepared different pH values by hydrothermal synthesis?pH=2-11?Monoclinic phase BiVO₄,the application of monoclinic phase BiVO₄ in the selective oxidation of benzyl alcohol to benzaldehyde.From the PL test,the fluorescence signal peak of BiVO₄ with pH=7 is the weakest and the intensity is the lowest Optimal catalyst.From SEM test,it can be seen that BiVO₄ with pH=7 has an octahedral cubic structure.The smooth surface provides a large number of active sites for the reaction.The catalyst has the highest activity.The control of different catalysts,solvents,alkalis and other variables optimizes the reaction conditions,making benzene The conversion rate of selective oxidation of methanol to benzaldehyde is the highest,and the conversion rate of the reaction reaches 83.5%.The effect of alcohol derivatives on the reaction is explored,and the circulation ability of the catalyst is tested to further explore the stability of the catalyst.At the end of the experiment,the catalyst was tested for active species.