DFT study on the interaction of TiO2 (001) surface with HCHO molecules

The interactions of formaldehyde (HCHO) molecule with TiO2 (001) surface were studied using density functional theory calculations. HCHO molecules are dissociated by the cleavage of C-H bonds after adsorption on TiO2 surface. The strong interactions between HCHO melecules and TiO2 surface are largely attributed to the bonding of hydrogen of HCHO and oxygen of TiO2 surface, which is mainly from the hybridization of the H ls, O 2p and O 2s. The newly formed H-O bonds cause the structure changes of TiO2 surface, and lead to the cleavage of O-Ti bond of TiO2 surface. The C-O bond that the dissociated remains of HCHO and newly formed H-O bond can be oxidized to form carbon dioxide and water in subsequent action by oxygen from the atomosphere. The charges transfer from HCHO to TiO2 surface, and the sum amount of the charges transferred from four HCHO molecules to TiO2 surface is bigger than that from one HCHO molecule to TiO2 surface due to the combined interaction of four HCHO molecules with TiO2 surface. (C) 2017 Published by Elsevier B.V.