Doping
is known to be an excellent and simple way of catalyst design. Although
notable progress has been made in understanding the reactivity and
catalytic activity of gas-phase and supported gold clusters, very
few studies have been carried out on the doped gold clusters. In the
present work, we have carried out density functional theory calculations
to investigate the effect of silicon doping on the reactivity and
catalytic activity of gold nanoclusters. The present work particularly
focuses on the adsorption and activation of molecular oxygen on the
pristine and silicon-doped gold clusters. The results confirm that
the silicon-doped Au7Si cluster shows considerable binding
and activation of the O2 molecule in comparison to the
pristine Au8 cluster as reflected in the relevant geometrical
parameters (O–O and Au–O bond lengths) and O–O
stretching frequency. However, silicon doping has no contrasting effect
on the reactivity and catalytic activity of the Au7 cluster.
In addition to the stronger binding and activation of the O2 molecule, the doped Au7Si cluster leads to a significant
reduction in the activation barrier (0.57 eV) for the environmentally
important CO oxidation reaction in contrast to the catalytically inactive
pristine Au8 cluster (1.22 eV). Thus, our results highlight
the critical role of doping foreign impurities for future endeavors
in the field of gold nanocatalysis.