文摘

We present results from our joint experimental and theoretical study of the reactivity of anionicand cationic gold oxide clusters toward CO, focusing on the role of atomic oxygen, different charge states,and mechanisms for oxidation. We show that anionic clusters react by an Eley-Rideal-like mechanisminvolving the preferential attack of CO on oxygen rather than gold. In contrast, the oxidation of CO oncationic gold oxide clusters can occur by both an Eley-Rideal-like and a Langmuir-Hinshelwood-likemechanism at multiple collision conditions as a result of the high adsorption energy of two CO molecules.This large energy of CO adsorption on cationic gold oxide clusters is the driving force for the CO oxidation.Therefore, in the presence of cationic gold species at high pressures of CO, the oxidation reaction is self-promoting (i.e., the oxidation of one CO molecule is promoted by the binding of a second CO). Our findingsprovide new insight into the role of charge state in gold-cluster-based nanocatalysis.