The adsorption and activation of formic acid on different anatase TiO2 surfaces

Abstract

Formic acid photodegradation is one of the most important reactions in organic pollution control, and helps to improve the hydrogen generation efficiency in titanium dioxide catalyzed water photodecomposition. Based on density functional theory and ReaxFF molecular dynamics, the adsorption, diffusion and activation of formic acid on the different anatase TiO2 (1 0 1), (0 0 1), (0 1 0) surfaces are investigated. The result shows that the adsorption of COOH on anatase TiO2 surface shrinks the energy gap between the dehydrogenation intermediate COOH and HCOO. On the anatase TiO2 (101) surface, the formic acid breaks the O–H bond at the first step with activation energy 0.24 eV, and the consequent break of α-H become much easier with activation energy 0.77 eV. The dissociation of α-H is the determination step of the HCOOH decomposition.