Coordination-Dependent Kinetics in the Catalysis of Gold Nanoclusters

A coordination-based kinetic model was used to explore the turnover frequency (TOF) in the oxidation of carbon monoxide on gold polyhedral nanoclusters. The Debye energy model was used to determine the Gibbs energy of bare nanoclusters. An empirical energy model derived from density functional theory (DFT) and thermodynamics was used to determine the size dependence of the Gibbs adsorption energy. A thermodynamic approach was used to model the kinetics of CO oxidation on gold nanoclusters. The adsorption was modeled with a Langmuir-Hinshelwood (L-H) mechanism and also a mechanism (Eley-Rideal, E-R) where oxygen interacts with sites on the cluster support. The coordination, shape, and the Gibbs energy of adsorption were found to be important factors in replicating experimental TOF dependencies. The data from the L-H mechanism was shown to model the experimental results more closely. The mass activity of icosahedra for this reaction shows a good similarity with the experimental data. This work provides guidance for different distributions due to shape and size when determining the TOF and the mass activity.