Controllable Preparation Of Nano VO₂（B） And Functional Application

As one of the isomers of vanadium dioxide,VO₂（B）has received more and more attention in recent years due to its excellent peroxidase-like activity and its potential for lithium battery applications.Among the currently known vanadium oxides,VO₂（A）,VO₂（B）and V₂O₅ have been confirmed to have peroxidase-like activity.However,compared with natural enzymes,the catalytic activity of these vanadium oxides still has a large gap.This article focuses on the controllable preparation of VO₂（B）and the evaluation of its peroxidase-like activity.By XRD,XPS,SEM,Raman and other characterization analysis techniques,the preparation process,microstructure and surface chemical state of VO₂（B）powder The main research work and important results of the mechanism of peroxidase-like activity are as follows:（1）with the help of SEM,XRD,Raman and XPS analysis and characterization methods,studied the effect of PVP on the particle size,crystal structure and surface chemical state of VO₂（B）powder.The results show that the surfactant PVP does not significantly change the crystal structure type of the product,but it has a certain inhibitory effect on the VO₂（B）grain growth,so that VO₂（B）has a tendency of preferential growth along the（110）crystal plane and the grain size of the powder are reduced.At the same time,as the amount of PVP added increased,the V⁴⁺content on the surface of the VO₂（B）particles increased and the V⁵⁺content decreased.The results of peroxidase-like activity test showed that appropriate amount of PVP could increase the peroxidase-like activity of VO₂（B）powder by 0.89 times.（2）The prepared VO₂（B）powder was rapidly treated with hydrogen peroxide,With the help of SEM,XRD,Raman and XPS,the influence mechanism of hydrogen peroxide treatment on the crystal structure and surface chemical state of VO₂（B）powder was studied.The results showed that the morphology of the vanadium oxide produced after treatment changed significantly.The main components of vanadium oxide are VO₂（B）and V₂O₅.The V⁵⁺content on the surface of the newly formed vanadium oxide increased significantly and the V⁴⁺content decreased.The test results of peroxidase-like activity showed that the peroxidase-like activity of vanadium oxides produced by the appropriate amount of hydrogen peroxide treatment was increased by 13 times.At the same time,the optimum temperature and optimum PH of vanadium oxide peroxidase were 40℃ and 4.0,respectively.Enzyme kinetic test results show that the vanadium oxide has a good affinity for the substrate.（3）Graphene oxide was added during the process of preparing VO₂（B）powder by hydrothermal method,With the help of SEM,XRD,Raman and XPS analysis and characterization methods,the effect of graphene oxide on the particle size,crystal structure and surface chemical state of VO₂（B）powder was studied.The results showed that graphene oxide did not significantly change the crystal structure type and morphology of the product.With the increase of the amount of graphene oxide added,the V⁵⁺content on the surface of VO₂（B）particles increased first and then decreased.The test results of peroxidase-like activity show that the appropriate amount of graphene oxide can increase the peroxidase-like activity of VO₂（B）powder by 2.67 times.