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

9:45 AM - 10:00 AM JST(12:45 AM - 1:00 AM UTC)

[3E04] Surface chemistry of methanol on TiO₂(110): Effect of pressure on methanol adsorption

*Can Liu¹, Boyang Liu¹, Kotaro Takeyasu¹, Satoru Takakusagi¹ (1. Institute for Catalysis, Hokkaido University (Japan))

Methanol adsorption on TiO₂(110) was investigated to clarify how gas pressure affects adsorbed species on fivefold-coordinated Ti⁴⁺ sites. While methanol dissociates only at oxygen vacancies under UHV, high-pressure methanol exposure (~1 Pa) produces a dense quasi-(2×1) layer of methanol adsorbates on Ti⁴⁺ rows. STM reveals two contrasts assigned to molecular methanol and methoxy species. The coverage increases with dose and saturates at 0.4–0.45 ML, with an apparent sticking coefficient of 2×10^-5, about four orders of magnitude lower than on Pt/TiO₂(110). The pressure-dependent adsorption is discussed by analogy with water aggregation-induced hydroxylation on MgO(100), suggesting that local methanol/methoxy/hydroxyl ensembles may stabilize adsorbates and promote ordering on Ti⁴⁺ sites.

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