Theoretical Study On Carbon Monoxide Catalytic Oxidation By Noble Metal Clusters

For gas like carbon monoxide,its popularity is derived from the abundant sources and toxic nature in certain concentration.Also,because it is widely distributed and hard to recycle,it brings tremendous side-effects on the contemporary environment and numerous problems for the development of chemical industry and mineral industry.Hence,research of the catalyzed oxidation of carbon monoxide has long been a topic issue.In the last century,small-sized noble metals,being active constituent catalysts,are attracting great concern for its excellent catalytic performance of low-temperature,efficiency and long operating life.Different options for supported substrates also bring numerous possibilities of improving catalytic efficiency.In this essay,we will use density functional methods to research and explore the absorption of single oxygen atoms on the cluster of n(n=1-8)gold atoms,and then systematically research on nano-sized vanadium oxygen clusters bearing the single gold atom as the catalyst and after the activation and absorption of carbon monoxide transformation,we will explore the specific catalytic procedure and the electron transfer of absorption and activation,through a contrast of clusters of similar basals which are bearing Ag.Based on the stable configuration of the adsorption of vanadium oxygen cluster V3Oyq(y = 6-8,q = ± 1 or 0)on Au/Ag found through the genetic algorithm previously,with further CO adsorption work,we discovered that the trend of the two CO absorption is similar to that of atomic number and quantity of electric charge,but overall,Au cluster has better adaptability than the Ag cluster on the adsorption of CO.Moreover,CO is largely more likely to be adsorbed on the metal sites in the cluster(Au/Ag>V>O),and this tendency is closely related to the initial adsorbing position of the noble metal on the cluster.The search for transitional states of the representative clusters(AuV3O7_v and AgV3O7_o)reveals the fact that they are not appropriate in the thermodynamics and kinematics on their reaction of catalyzing CO and CO2 forming.However,the cluster ability of Au is higher than that of Ag.In addition,through analyzing the natural population,electrostatic potential,and the abilities of adsorption and desorption,we have compared the electronic capabilities of Au and Ag and systematically analyzed the reason for CO selection of the adsorption site and the stability of each cluster before and after adsorption.It is expected that through this study,we can give a reasonable explanation for the observed phenomenon of the catalytic reaction and acquire the adsorption position and means of carbon monoxide on the cluster,revealing the micro-mechanism of the monatomic adsorption of the noble metal and the catalytic oxidation of carbon monoxide.We have summarized the major factors affecting the reactivity and selectivity on molecular level,providing theoretical guidance for the rational design of bullion monatomic catalysts.