[3E01-11] Surface Science / Chemical Property (SS2)

10:15 AM - 10:30 AM JST(1:15 AM - 1:30 AM UTC)

[3E06] Operando observation of the interaction between CO₂/H₂ gases and Ru(0001) surface using synchrotron-based ambient pressure X-ray photoelectron spectroscopy

*Yu Murano¹, Masafumi Horio¹, Yifu Liu¹, Haruto Sakurai¹, Yuki Tsujikawa², Yoko Saito³, Takeru Nakashima³, Yasunobu Ando³, Hiroshi Kondoh², Kenichi Ozawa⁴, Iwao Matsuda¹ (1. The Institute for Solid State Physics, The University of Tokyo (Japan), 2. School of Science and Technology, Keio University (Japan), 3. Institute of Integrated Research, Institute of Science Tokyo (Japan), 4. Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) (Japan))

In this study, we investigated CO₂ activation on Ru(0001) surface using APXPS under CO₂ and/or H₂ gases. A series of experiments were performed at beamline BL08U in NanoTerasu, where XPS can be measured in the pressure range from UHV (10^-10 mbar) to atmospheric pressure (1 bar). Under 0.1 mbar CO₂ at 300 K, CO* at the atop site (CO_t*) and atomic oxygen at hollow sites (O*) were observed, supporting the CO₂ dissociation pathway. Subsequent introduction of 0.3 mbar H₂ at 300 K resulted in the removal of O* and the formation of additional CO* species instead, which was assigned to CO* at the bridge site (CO_b*). The stability of the co-adsorbed phase of CO_t* and CO_b* was confirmed by the first principles calculations. Those two types of CO* species dissociate into carbon species including atomic carbon (C*), as a source of methanation, at different temperatures. The difference in their reactivity may be a key factor for low-temperature activity of Ru catalysts. The findings of this study would provide the basis for tailoring the selective generation of CH₄.

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