[2A06-13] Surface Science / Chemical Property (SS2)

4:30 PM - 4:45 PM JST(7:30 AM - 7:45 AM UTC)

[2A11] In situ observation of the dissociation process of CO₂ on a rhodium single-crystal surface

*Akitsugu Fujii¹, Go Okawara¹, Yuta Koganeya¹, Yuki Tsujikawa¹, Hiroshi Kondoh¹ (1. Keio University (Japan))

Developing efficient CO₂–reduction catalysts requires a fundamental understanding of CO₂ dissociation on metal surfaces. Using polarization-modulated infrared reflection absorption spectroscopy (PM–IRRAS) and ¹³CO₂ at a low pressure of 3.6×10^-6 Torr, we observed a clear top–¹³CO band on Rh(111), demonstrating that CO₂ dissociates on the surface. Comparison with spectra obtained during ¹³CO exposure confirmed that this feature does not originate from trace ¹³CO impurities. The top–¹³CO intensity produced from ¹³CO₂ was much smaller than that from adsorbed ¹³CO, indicating that dissociation occurs mainly at defect sites rather than terrace sites. Furthermore, co–exposure of H₂ or H₂O did not change the intensity of top–¹³CO peak, suggesting that neither species promotes or suppresses CO₂ dissociation under low–pressure conditions. These results provide insight into the elementary steps governing CO₂ activation on the Rh surfaces.

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