Chemisorption of CO and H on Pd, Pt and Au nanoclusters: a DFT approach

We have performed a theoretical study of pure metal nanoparticles (Pd/Pt/Au) and their interaction with CO molecules and atomic hydrogen, in order to investigate chemisorption effects of relevance to catalysis by nanoparticles. First-principles density-functional local relaxations are used to investigate the effect of CO and H adsorption on six structural motifs. The results of the energetic crossover and structural deformations are analyzed in terms of the interplay between metal-metal interactions (including internal and surface stress) and CO-metal and H-metal interactions. It is found that H adsorption releases surface stress, thus favoring 5-fold symmetry motifs, whereas CO adsorption produces a flattening of the potential energy surface of the metal clusters.