Bonding of Methyl Phosphonate to TiO2(110)

• Published in: Journal of physical chemistry. C Vol. 114; no. 40; pp. 16983 - 16988
• Main Authors: Pang, C. L, Watkins, M, Cabailh, G, Ferrero, S, Ngo, L. T, Chen, Q, Humphrey, D. S, Shluger, A. L, Thornton, G
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.10.2010
• Subjects: Physics
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp1018923

We have used scanning tunneling microscopy (STM), noncontact atomic force microscopy (NC-AFM), low energy electron diffraction (LEED), and ab initio calculations to study adsorbates resulting from exposure of rutile TiO2(110)1 × 1 to methyl phosphonic acid (CH3PO(OH)2). At low exposures, adsorbates appear on the 5-fold coordinated Ti (Ti5c) rows. As the coverage of adsorbates approaches 0.5 ML, STM images show an ordered 2 × 1 overlayer consistent with LEED. We propose that the phosphonic acid is deprotonated with the resulting phosphonate bridging across two adjacent Ti5c atoms in the [001] direction. This bridging conformation would lead to the observed 2 × 1 overlayer and is analogous to that found for a range of carboxylates adsorbed on TiO2(110).