Density Functional Theory Based Studies On The Structure And Bonding Of Pt Alloy Clusters

Excellent properties of small alloy clusters in materials chemistry, surfacescience, quantum chemistry, condensed matter physics and other interdisciplinaryresearch have been widely exploited,Pt alloy clusters with good adsorption, bindingcharacters, and extensive application, attracts extensive attentions. Nanoclusters andmicroscopic composite materials containing Pt also get more and more interested aswell.At present, studies on Pt alloy small clusters focuses on adsorption, catalysis,fuel cells and so on. Most researches of the Pt alloy clusters focus on a few types ofalloys and there are few studies on the bonding pattern of Pt based alloy across theperiodic table. The present work studied the geometric and electronic structure thePt alloy clusters (of two atoms and three atoms) with transition metals in the fourth,fifth, and sixth periods with density functional theory based method The structuraldate and properties include bond lengths, bond angles, charge, bond energy, bondorder, frequency, Fukui functions and so on.Among the Pt alloy clusters with two atoms, the clusters with elements fromthe fifth and sixth period have higher stability in structure with shorter bond lengthsand different vibrational frequencies from those of the elements from the fourthperiod. In the Pt alloy clusters with three atoms, we analyzed PtM2and Pt2M twostructures. In PtM2structures with M from the fifth period, the bonding strength isstronger than those from the fourth and sixth period. The order of pros and cons ofelectronic is the fourth <the fifth <the sixth. The alloy cluster with M from â…¢ B,â…§ B groups have the largest HOMO-LUMO energy gap. Compared to the alloyclusters with M from the fourth and sixth period, the activity of the alloy clusterswith M from the fifth period have the highest reactivity, most of the active centersare M atoms. In the Pt2M clusters, the bonding strength of M from the fourth andfifth period is stronger than those from the sixth period, in addition to Y, Zr, Nbthree structures in fifth period, other structures of two period have bond betweentwo Pt atoms. With the same structure as that PtM2, Y atom has the most electrons.Bond order is the largest in â…¦ B group. Comparison of the data in two structures,the bonding capacity of Pt2M is stronger than PtM2, structural stability is better thanthe latter. Fukui function is used to characterize the chemical activity for those alloyclusters. In the three atomic clusters, Pt2M activity is stronger than PtM2structure,but the former is mainly based on the active center of Pt atoms, while the latter ismainly dominated by M atoms.