Preparation And Performance Study Of Bismuth Molybdate Photocatalyst

In recent years,the harm caused by the abuse of antibiotics poses a serious threat to the ecological environment and human health,and is one of the urgent problems to be solved in today’s society.Semiconductor photocatalysis technology is considered a promising technology due to its environmental friendliness,economic feasibility,and high oxidation activity.However,the development of an efficient and stable photocatalyst is still a huge challenge,Most photocatalysts have poor photocatalytic activity due to their slow transport speed of photogenerated carriers and easy recombination of electron holes.Bi₂Mo O₆has a narrow band gap and unique layered structure,which can utilize visible light.However,pure phase bismuth molybdate has low optical quantum efficiency and slow electron hole transmission.Using ion doping and semiconductor recombination to modify it is an effective approach.In this paper,Bi₂Mo O₆was prepared by hydrothermal method.The modification of Bi₂Mo O₆was studied using Co ion doping and composite with Bi OCl_0.7I_0.3semiconductor.Evaluate the photocatalytic performance of the catalyst through photocatalytic degradation experiments,explore the impact on the kinetic behavior of photogenerated carriers in the catalyst,and propose the degradation mechanism of the catalyst by combining characterization methods.This study provides a theoretical basis for the study of highly active bismuth molybdate photocatalysts.The main contents are as follows:（1）Co²⁺doped Bi₂MoO₆was prepared by hydrothermal method.Co ion doping does not alter the crystal structure of the catalyst（XRD）,but increases the visible light absorption range（UV-vis）.The experimental results of photocatalytic degradation showed that Co ion doping improved the photocatalytic activity of the catalyst,with 5%Co BMO photocatalyst having the best activity and good stability.Based on the comprehensive XPS,PL and electrochemical test results,it can be seen that Co ion doping effectively reduces the recombination efficiency of photogenerated electron hole pairs in the catalyst,promotes the transport rate of photogenerated carriers,and improves its photocatalytic activity.（2）Bi₂MoO₆-BiOCl_0.7I_0.3heterojunction was constructed by in-situ etching.XRD and SEM results showed that BOCI was successfully deposited on the surface of BMO,and the absorption edge redshift of BOCI composite enhanced visible light absorption.The experimental results of photocatalytic degradation show that semiconductor recombination promotes the photocatalytic reaction,and the optimal degradation efficiency can reach 86%.Based on XPS,energy band analysis and electrochemical test results,it can be seen that the improvement in performance is mainly attributed to the construction of heterojunctions promoting the separation of photogenerated carriers,which is conducive to the progress of photocatalytic reactions.（3）Bi₂MoO₆-BiOCl_0.7I_0.3heterojunction was constructed by in-situ growth method.The results showed that the photocatalyst prepared by this method exhibited excellent performance in the degradation of TC,with a degradation efficiency of 90%for the 8:2BMO-BOCI sample after 40 min of illumination,and the photocatalyst constructed by this method had higher photocatalytic activity.Based on XPS,energy band analysis and electrochemical testing results,it can be seen that this method constructs a heterojunction between two semiconductors,which combines more closely and has more active sites.Photogenerated carriers transfer faster,forming a strong electronic coupling effect,and effectively improving the separation efficiency of photogenerated carriers.（4）BiOCl_0.7I_0.3nanosheet was prepared by hydrothermal method,and Bi₂Mo O₆-Bi OCl_0.7I_0.3van der Waals heterojunction photocatalyst was further constructed by simple wet mixing.The results showed that the photocatalytic performance of the catalyst was improved,and the degradation efficiency could reach 94%after 40 minutes of illumination.Based on XPS,energy band analysis and electrochemical test results,it can be seen that the improvement in photocatalytic performance is mainly attributed to the formation of a Van der Waals heterojunction between catalysts through surface stacking,greatly increasing the contact area of the two semiconductors,accelerating the electron hole transport rate between semiconductors,and effectively improving the separation efficiency of photocatalyst photogenerated carriers.