Computational Studies of the Interaction of Carbon Dioxide with Graphene-Supported Titanium Dioxide

The interaction of carbon dioxide (CO2) with titanium dioxide (TiO2) supported on graphene (GR) and epoxy-enhanced graphene (GR-O) was investigated using density functional theory (DFT) calculations and compared with the interaction on unsupported TiO2 systems. Adsorption energies, charge density differences, and activation barriers were calculated. TiO2 clusters, comprising two to four TiO2 units were considered. We show that the carbon support influences the binding energy of CO2 significantly when chemisorbed, and the molecule is bound in a bent VI:614 40 configuration. The epoxy oxygen connection of GR-O with TiO2 leads to a further increase in the binding energy of CO2, as does increasing the size of the TiO2 cluster, due to a higher charge delocalization on the GR sheet.