Complexity of CO2 Activation and Reaction on Surfaces in Relation to Heterogeneous Catalysis: A Review and Perspective

Abstract

We discuss activation and reaction of CO2 on oxide-supported Au nanoparticles in connection with the preparation and characterization of model systems for heterogeneous catalysts, referring mostly to our own studies in the field. These systems are based on crystalline oxide thin films grown on metal substrates, which allows us to characterize them at the atomic scale. Depending on preparation conditions, the oxide-supported Au nanoparticles assume a particular morphology that is largely controlled by electron transfer from the metal substrate through the oxide film or from dopants in the oxide film. If such an electron transfer to the Au nanoparticles is possible, they assume a two-dimensional morphology and electrons can flow from the particle rim to attached CO2 molecules. This electron transfer leads to the formation of oxalate species that may spill over to the oxide substrate and are available for further reactions. The required structural parameters and the possibilities to monitor the spill-over process are discussed in detail in this paper.