H2/D2 exchange reaction on mono-disperse Pt clusters: enhanced activity from minute O2 concentrations

Abstract

The H₂/D₂ exchange reaction was studied on mono-disperse Pt₈ clusters in a μ-reactor. The chemical activity was studied at temperatures varying from room temperature to 180 °C using mass spectrometry. It was found that minute amounts of O₂ in the gas stream increased the chemical activity significantly. XPS and ISS before and after reaction suggest little or no sintering during reaction. A reaction pathway is suggested based on DFT. H₂ desorption is identified as the rate-limiting step and O₂ is confirmed as the source of the increased activity. The binding energy of platinum atoms in a SiO₂ supported Pt₈ cluster is found to be comparable to the interatomic binding energies of bulk platinum, underlining the stability of the model system.