Synergetic effects in CO adsorption on Cu-Pd(111) alloys

We present density functional calculations for the interaction of CO on dif ferent Cu-Pd(111) bulk and surface alloys. The modification of the adsorpti on properties with respect to hose of the adsorption on pure Cu(111) and Pd (111) is described in terms of changes in the adsorption sites and the chan ge of the electronic structure occurring upon alloying. The presence of coo perative, synergetic. effects is found to be important specially for Cu-ric h bulk alloys. In this case. a larger adsorption energy is found for the in active component than for the pure inactive system. This activation induces a larger reactivity than might be expected, from the position of the Pd d- band. for the active Pd centers. (C) 2001 Elsevier Science B.V. All rights reserved.