CO2 adsorption on Ti3O6-, which serves as a model for an oxygen vacancy on a titania surface, is studied using infrared photodissociation (IRPD) spectroscopy in combination with density functional theory (DFT) and coupled cluster computations, as well as a recently developed multicomponent artificial force induced reaction method. The IRPD spectra of D2-tagged [(Ti3O6)(CO2)n]-, with n = 1, 2, are reported in the spectral window of 450-2400 cm-1 and assigned based on a comparison to harmonic IR spectra from the DFT calculations. We find that CO2 binding leaves the unpaired electron largely unperturbed. The first two CO2 molecules adsorb chemically to Ti3O6- by incorporating a formally doubly negatively charged, either doubly or triply coordinated O atom to form a bidentate or tridentate bridging carbonate dianion (CO32-), respectively. The latter binding motif exhibits a characteristic IR signature in the form of an intense doublet of peaks near 1400 cm-1 stemming from two antisymmetric carbonate stretching modes.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films