CO2 Adsorption on Ti3O6 –: A Novel Carbonate Binding Motif

• Published in: Journal of physical chemistry. C Vol. 123; no. 13; pp. 8439 - 8446
• Main Authors: Debnath, Sreekanta, Song, Xiaowei, Fagiani, Matias R, Weichman, Marissa L, Gao, Min, Maeda, Satoshi, Taketsugu, Tetsuya, Schöllkopf, Wieland, Lyalin, Andrey, Neumark, Daniel M, Asmis, Knut R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 04.04.2019
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.8b10724

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 (CO3 2–), 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.