CO₂ Capture by TiO₂ Anatase Surfaces: A Combined DFT and FTIR Study

In this work, by combining FTIR results with periodic DFT calculations, we highlight the role of different anatase surface sites in the CO2 adsorption and in the subsequent reactions. It is shown that CO2 is mainly adsorbed in linear form at the (101) surface, while the formation of a variety of surface carbonates is occurring at the (001) one. The role of coadsorbed water in the formation of surface bicarbonates is also investigated. All the structures identified by FTIR spectroscopy were modeled by DFT, and the adsorption geometries and the energy of formation for the surface species were carefully analyzed. For the most stable structures we also performed the calculation of the vibrational frequencies that were compared with the FTIR data.