Titanium dioxide (TiO2) has been studied and used in very wide range of areas, and in particular, the it has been taken as the model system to study adsorption behaviors of probe molecules as well as structure-activity relationship in catalysis. In our recent work, the adsorption behavior of small organic acid molecules at rutile TiO2(110) was investigated by means of density functional theory (DFT) calculations, corrected by on-site Coulomb corrections and long-range dispersion interactions. Our calculation results show that carboxylic acids prefer to dissociatively adsorb in bridging bidentate configuration, and it induces significant surface relaxation at the adsorption site, which also affects other surface atoms nearby. Interestingly, we have shown that such adsorption induced relaxations still maintain bond symmetries for surface Ti cations within the p(2×1) domain while they are drastically broken within the c(2×2) domain, giving rise to unstable Ti cations at the surface. This work not only explains the long lasting puzzle of the preferable occurrence of p(2×1) domain for the adsorbed carboxylic acids at rutile TiO2(110), it also proposes a novel scheme that metal oxide surfaces may follow when they are involved in the processes like surface functionalization and self-assembly. Very recently, a genetic algorithm based calculation strategy was also used to help determine the favorable surface structures of mixed oxide surfaces built on rutile TiO2(011), which are distinct from various known bulk phases.

Advances in theoretical studies of surface structures and adsorption of probe molecules at metal oxides

251st National Meeting (2016)

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