Interaction of carbon monoxide with Cu nanoclusters grown on alumina surface

The present work addresses the interaction of carbon monoxide with copper nanoclusters supported on an ultrathin alumina film grown on the Ni₃Al(111) termination, acting as a template for a highly ordered nucleation. Through accurate quantum-mechanical calculations combined with experimental data, it has been found that the dissociation of carbon monoxide occurs at the copper nanoclusters, at variance with extended surfaces. The detailed mechanism is explained at the atomic level, unveiling the effects of cluster finite size, reconstruction, support, and carbon monoxide coverage. The small size of the nanoclusters allows to achieve an exceptionally high local concentration of molecules at the cluster surface, considerably higher than the saturation limit for the single crystal surfaces. The high coverage facilitates the dissociation of the molecules, accompanied by carbon incorporation into the particles. We discuss the possibility of using other transition metals for an optimal seeding of the supported nanoparticles. In agreement with empirical findings, Pd is confirmed to be the best choice for a highly ordered nucleation.