Density functional theory study of ethylene adsorption on clean anatase TiO2 (001) surface

This work investigated the adsorption of C2H4 (ethylene) on anatase TiO2 (001) surface by means of first-principles calculation. Four adsorption configurations that correspond to two main types of interaction of ethylene-solid surface, namely π-bonded and di-σ-bonded interactions, are studied. We found that ethylene adsorbed on top of unsaturated Ti5c (five-fold coordinated Titanium) is the most stable configuration and this configuration corresponds to the π-bonded interaction. For the most stable configuration, the adsorption energy is calculated to be ~ − 0.2 eV (0.49 eV with vdW correction) and ethylene retains its initial sp2 planar configuration upon adsorption. Vibrational frequency analysis shows that some small modifications are observed for each reported vibrational modes of ethylene. These findings suggest that ethylene is weakly adsorbed on clean TiO2 surface and vdW interaction is found to have a significant contribution to the total binding energy of ethylene.