Study of pyridine and its derivatives adsorbed on a TiO2(110)–(1×1)surface by means of STM, TDS, XPS and MD calculation in relation to surface acid[ndash ]base interaction

Abstract

Pyridine, benzene, 2,6-dimethylpyridine (2,6-DMP), and m-xylene molecules adsorbed on a TiO₂(110)–(1×1) surface have been characterized by scanning tunneling microscopy, thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and molecular dynamics calculation to explore the structural features of acid–base interaction, which is relevant to acid–base catalysis of metal oxides. Individual pyridine and 2,6-DMP admolecules were successfully visualized by STM at room temperature. Those probe molecules were only weakly adsorbed on the surface and desorbed near room temperature. The absence of chemical bonds between the nitrogen atoms of adsorbed pyridine and 2,6-DMP and the Ti⁴⁺ atoms exposed to the surface was suggested, despite the presence of enough space for bonding on the Ti⁴⁺ atoms at the surface.