DFT study on stability and H2 adsorption activity of bimetallic Au79-nPdn (n=1-55) clusters

The stability and H-2 adsorption activity of bimetallic Au79-nPdn (n = 1-55) clusters were studied by density functional theory with GGA-PW91 functional. The stability order for four Pd substitution types is face > mid-edge > corner > edge, and the stability is improved with increasing Pd content. In contrast with the stability order, H-2 adsorption activity is corner approximate to edge > mid-edge > face. The Au36Pd43 (3) with Au:Pd approximate to 1:1 ratio and twenty-four Pd substitutions at (111) facets and nineteen Pd substitutions at sub-shell sites shows high stability and H-2 non-activated dissociation activity. The partial density of d-states and d band center revealed that the electronic properties are closely associated with the geometric characteristic and adsorption activity. Correlating the d band center epsilon(d) and the adsorption energies, the ed order agrees with the adsorption activity that the Pd substitution at edge and corner sites are more active than at face and mid-edge sites. (C) 2013 Elsevier B.V. All rights reserved.