First Principles Study Of BiRu_n(n=3-20) Clusters

In this thesis,the geometric structure and electronic properties of BiRu_n（n=3-20）clusters and the adsorption properties of some hazardous gas molecules are studied mainly by using the generalized gradient approximation of density functional theory,including the following aspects.（1）Most of these clusters exhibit low symmetry（e.g.,Cs）and generally have a cage-like polyhedral structure with Bi atoms as vertices,while the BiRu₆,BiRu₁₁,BiRu₁₂,and BiRu₁₇clusters exhibit high symmetry and high stability of C₅V.the BiRu_ncluster structures show growth properties,i.e.,by adding a Ru atom to BiRu_n-1to build The Ru_nclusters also follow a similar growth rule to form their respective geometrical structures.（2）Second-order energy difference calculations reveal that BiRu₅and BiRu₁₂exhibit relatively high thermodynamic stability.Given that BiRu₁₂and BiRu₆have the largest and smallest energy gaps Eg,respectively,the highest chemical stability and activity are predicted,respectively.The Vertical Ionization Potential（VIP）and Vertical Electron Affinity（VEA）show a decreasing and increasing trend with n,respectively.（3）Regarding the adsorption performance of these clusters on hazardous gas molecules,it was found that in BiRu₁₄and BiRu₂₀have excellent and good adsorption performance on CO and NH₃molecules,respectively,while NO and H₂S molecules have poor adsorption performance on these clusters.The above study will help to construct and characterize the electronic properties of BiRu_nclusters and explore their potential adsorption properties and prospects as sensors for hazardous gases.Next,the BiRu₁₂cluster in the BiRu_ncluster was selected,and the Bi elements were replaced by Pb and Tl elements,respectively,and the Ru elements were replaced by Rh and Pd elements,respectively,and then the minimum energy structures and related physicochemical properties of the Pb Ru₁₂,TlRu₁₂,BiRh₁₂,Bi Pd₁₂clusters and the adsorption properties on the hazardous gas molecules were calculated.（1）For XRu₁₂（X=Pb,Tl）and BiY₁₂（Y=Rh,Pd）cluster systems,the chemical stability of BiRh₁₂and Bi Pd₁₂clusters with high symmetry cage-like structures are higher than that of BiRh₁₂clusters with cubic structures.（2）Since the atomic radii of Ru,Rh and Pd gradually decrease,their electron affinity energies gradually increase,so the VEA values of the corresponding clusters gradually increase,while the VIP values gradually decrease.the stability of Pb Ru₁₂clusters is relatively higher.（3）For the adsorption properties of XRu₁₂（X=Pb,Tl）and BiY₁₂（Y=Rh,Pd）cluster systems,three hazardous gases,CO,NO and NH₃,were selected for calculation,and it was found that the four clusters,Pb Ru₁₂,TlRu₁₂,BiRh₁₂and Bi Pd₁₂,had the strongest adsorption for CO,the second best adsorption for NO and the weakest adsorption for NH₃.the weakest.（4）Since TlRu₁₂is the strongest cluster for CO adsorption,the nature of its adsorption of two CO molecules was further investigated,and it was found that the TlRu₁₂cluster still has strong adsorption properties when adsorbing two CO gas molecules.