Preparation Of Hydrogen Peroxide By Highly Selective Oxygen Reduction Reaction Of Tungsten And Molybdenum Oxide

With the increasing demand for hydrogen peroxide,the preparation of hydrogen peroxide by electro-catalytic oxygen reduction has attracted wide attention.Efficient oxygen reduction catalyst provides a feasible way for the preparation of hydrogen peroxide by two-electron oxygen reduction reaction（2e^-ORR）,and it has been widely concerned in the field of electrocatalytic preparation of hydrogen peroxide in recent years.Combined with the advantages of low cost,high stability and high selectivity of metal oxides,a series of high selectivity catalysts for electrocatalytic oxygen reduction to prepare hydrogen peroxide were obtained by adjusting the electronic structure and crystal structure of surface interface.The research contents of this paper are as follows:1.Phase regulation of WO₃for highly selective oxygen reduction to hydrogen peroxideThe regulation of phase structure can change the orbital splitting energy and Gibbs free energy of W-O,an intermediate of hydrogen peroxide reaction,thus improving the catalytic selectivity and activity of hydrogen peroxide preparation.Tungsten trioxide catalysts with different phase structures were successfully prepared,and cubic tungsten trioxide showed excellent catalytic performance.The selectivity of two-electron oxygen reduction is as high as 90%,and the yield reaches 179 mmol g_cat^-1h^-1,which is better than all the transition metal oxide catalysts reported in the past under the same conditions.This provides a new guidance scheme for designing catalysts with high selectivity and high activity.2.Preparing highly selective hydrogen peroxide by adjusting the concentration of oxygen vacancies on the surface of molybdenum trioxideA new method to regulate the catalytic selectivity of two-electron oxygen reduction reaction by using the concentration of oxygen vacancy was developed.Mo O₃catalysts with different oxygen vacancy concentrations were prepared by hydrothermal reduction in two steps.Through XPS and EPR tests,the concentration of oxygen vacancies on the surface of Mo O₃was accurately analyzed.Electrochemical tests showed that Mo O_3-x-400catalyst with moderate oxygen vacancy concentration showed the best performance,with a hydrogen peroxide selectivity of 93%and the yield of 310 mmol g_cat^-1h^-1.This study further proves the volcanic diagram relationship between the catalytic selectivity of two-electron oxygen reduction and the concentration of oxygen vacancy in MoO₃ catalyst,which provides a new method for preparing two-electron oxygen reduction catalysts with excellent performance.