Paper IS-ThA1
The Influence of Oxygen on the Catalytic Interaction between CO₂ and Copper studied by High Pressure X-ray Photoelectron Spectroscopy

Thursday, November 10, 2016, 2:20 pm, Room 101C

CO₂ is a source for the production of carbon based fuels, such as methanol, and presents an attractive alternative to fossil fuels. Copper is an ideal catalyst for the reduction of CO₂, as it is able to direct reactions through stable intermediates, e.g. CO. An important question concerns the influence of oxygen on the catalytic activity and whether oxides are formed on the surface. As this system is an excellent material for the reduction of CO₂ a detailed understanding of the basis of its catalytic activity is essential and absolutely necessary for any further development.

X-ray photoelectron spectroscopy (XPS) is used widely in the solid-state sciences but due to its nature as an ultra high vacuum technique (pressure 10^-9 mbar) it is not possible to study gas-solid interfaces. High-pressure XPS (HPXPS) is an advanced method which allows the measurement of solid samples at elevated pressures of between 1 and 30 mbar. This work presents results on the interaction of CO₂ and CO₂/O₂ with the surface of polycrystalline Cu followed by HPXPS. Cu 2p core levels, as well as the Cu L₃M_4,5M_4,5 Auger line are used to investigate the state of the Cu surface. The C 1s and O 1s core levels are used to track the interaction between CO₂/O₂ and Cu and are compared to CO₂/O₂ gas phase measurements.

Ultimately, the presented results provide a starting point for the detailed understanding of these catalysts and lead to the identification of possible ways to further improve and develop their properties.