Formaldehyde adsorption geometry and energies over TiO2(110) rutile surface

• Published in: Chemical physics letters Vol. 572; pp. 125 - 129
• Main Authors: M. R. Muir, J., Idriss, H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.05.2013
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2013.03.070

•Two stable molecularly adsorbed modes of formaldehyde are observed on TiO2 (110).•One perpendicular to the surface (110) plane and one tilted along the [11¯0] direction.•The η1(O) tilt geometry is found to be more stable than the η1(O) straight geometry.•For the tilted adsorption HOMO O2px, has considerable overlap with Ti 3d states.•For the perpendicular adsorption HOMO-2, O 2pz, has the strongest overlap. The adsorption modes and electronic structure of formaldehyde on TiO2(110) were investigated using the PWDFT method. The η1(O) adsorbed mode has two stable structures: perpendicular to surface plane and tilted along the [110] direction. The η1(O) tilt geometry is ∼25kJ/mol more stable than the η1(O) straight geometry. In the case of tilted adsorption, orbital 2b2 of formaldehyde (HOMO; O2px) has considerable overlap with Ti3d states while in the case of perpendicular adsorption, orbital 5a1 (HOMO-2; O2pz) has the strongest overlap. All lower energy adsorbed formaldehyde orbitals have better Ti overlap in the straight configuration, however.