BOND ORDER CONSERVATION MODEL STUDIES OF H-2, O-2 AND CO DISSOCIATIONON METALLIC NANOSTRUCTURES

The bond order conservation-Morse potential (BOC-MP) model has been us ed to study the dissociation of H-2, O-2 and CO molecules on Ag, Cu, N i, Pd and Pt nanostructures. For particles with total number of atoms (N-T) upto 500, a moderate increase in the chemisorption energy with p article size has been found in qualitative agreement with the experime ntal results. For N-T in the range of 40 to 200, the activation for di ssociation, Delta E drops exponentially; and for N-T > 400, Delta E de creases very slowly. Delta E for O-2 dissociation on Cu and Ni is foun d to change sign from positive to negative at N-T between 80 and 140; while Delta E for O-2 dissociation on Ag, Pt and Pd remains positive f or all sizes of the nanostructures.