Real-Time Observation of Reaction Processes of CO2 on Cu(997) by Ambient-Pressure X-ray Photoelectron Spectroscopy

The reaction of CO 2 on the vicinal Cu(997) surface at 340 K under CO 2 gas pressure of 0.8 mbar was investigated by ambient pressure X-ray photoelectron spectroscopy. A main reaction product on the surface was identified as carbonate (CO 3 ), based on estimation of the composition ratio of oxygen to carbon. CO 3 was produced on the surface through the reaction of CO 2 with oxygen formed from CO 2 dissociation. The amount of adsorbed CO 3 was increased and saturated as time elapsed. After saturation of adsorbed CO 3 , atomic oxygen appeared on the surface, indicating that CO 2 dissociation into CO and O continued to take place. The present study shows the importance of CO 3 intermediate in the CO 2 chemistry on stepped Cu surfaces.