Atomic-scale modeling of CO interaction with supported Cu nanoclusters: steering reactions towards the Boudouard process

JIMENA A. OLMOS ASAR; ERIK VESSELLI; A. BALDERESCHI; MARIA PERESSI

Varsovia

Encuentro; EMRS Fall Meeting; 2014

EMRS

Supported metal nanoparticles are extremely interesting candidates for developing efficient catalysts. In addition to their peculiar intrinsic properties due to the nanosize and high concentration of active sites, their behaviour is also determined by the support, which can act as a template to synthesize ordered arrays of well-defined equally sized nanoparticles and to prevent sintering at high temperatures and consequent deactivation of the catalytic devices. Ultrathin film of alumina onto a Ni3Al(111) surface has been recently identified as a good template for highly ordered self-assembly of Cu nanoclusters.With a combined approach of highly accurate surface science experimental techniques and Density Functional Theory numerical simulations we have investigated the mechanism of nucleation, anchoring, and growth of Cu clusters onto alumina/Ni3Al(111) film and their interaction with carbon monoxide. As widely known, the alumina template is inactive with respect to CO adsorption. In contrast, CO attaches to the Cu clusters, and dissociation is observed with conversion into carbon dioxide (Boudouard reaction), proceeding via an Eley-Rideal mechanism yielding accumulation of carbide into the bulk of the clusters. The role of finite-size effects, local coverage and support are discussed for different reaction paths.