Presentation Information
[1C08]Bridging the Pressure Gap in Molecular Adsorption: STM Study of High-pressure Methanol Adsorption on TiO2(110)
*CAN LIU1, Bang Lu1, Kotaro Takeyasu1, Satoru Takakusagi1 (1. Institute for Catalysis, Hokkaido University)
To address the pressure gap in surface catalysis, we investigated methanol adsorption on TiO2(110) by performing STM imaging after exposing the surface to methanol vapor at 0.1–100 Pa. Under these elevated pressures, a near-ordered and stable adsorption structure was observed, in contrast to the adsorption under low-pressure (10-6~10-8 Pa) methanol vapor. STM images revealed bright and dark spots aligned along the [001] direction, with interspot spacing of two or three times the distance between adjacent Ti4+ sites. DFT simulations identified the bright features as dissociated methoxy species and the dark ones as intact methanol molecules. These adsorbates remained stable under UHV conditions and began to desorb only above 150 oC. These results demonstrate that pressure significantly alters the adsorption behavior, underscoring the importance of high-pressure studies in accurately capturing surface chemical processes.