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 behaviors of probe organic molecules at rutile TiO2(110) and (011) surfaces were 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. For the rutile TiO2(011) with unique reconstructed conformation, its structures can undergo further restructuring upon interaction with various molecules, which can dramatically affect its activity. In particular, synergic effect of adsorbates causes a strictly directional re-organization of the substrate, which results in one-dimensional adsorbate cluster formation.

Theoretical studies of adsorption and self-assembly of probe organic molecules at metal oxide surfaces

253rd National Meeting (2017)

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