Hydrogen bonding controls the dynamics of catechol adsorbed on a TiO2(110) surface

S-C. Li1, L.-N. Chu2, X.-Q. Gong2, U. Diebold1,3

1Department of Physics, Tulane University, New Orleans, Louisiana 70118, U.S.A.
2Labs for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
3Institut für Angewandte Physik, Technische Universität Wien, 1040 Wien, Austria

Science 328 (2010) 882-884

Direct studies of how organic molecules diffuse on metal oxide surfaces can provide insights into catalysis and molecular assembly processes. We studied individual catechol molecules, C6H4(OH)2, on a rutile TiO2(110) surface with scanning tunneling microscopy. Surface hydroxyls enhanced the diffusivity of adsorbed catecholates. The capture and release of a proton caused individual molecules to switch between mobile and immobile states within a measurement period of minutes. Density functional theory calculations showed that the transfer of hydrogen from surface hydroxyls to the molecule and its interaction with surface hydroxyls substantially lowered the activation barrier for rotational motion across the surface. Hydrogen bonding can play an essential role in the initial stages of the dynamics of molecular assembly.

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Reprints available from Ulrike Diebold or Michael Schmid (schmid at iap_tuwien_ac_at).

This work was featured in Chemical & Engineering News Vol. 88 (2010) 29.