Electronic structures of bare and terephthalic acid adsorbed TiO₂(110)-(1 × 2) reconstructed surfaces: origin and reactivity of the band gap states

Abstract

Combined core level spectroscopy, valence spectroscopy and density functional theory studies have probed the terephthalic acid (TPA) adsorption behavior and the electronic structure of the rutile TiO2(110)-(1 × 2) reconstructed surface at room temperature. The TiO2(110)-(1 × 2) reconstructed surface exhibits an electron rich nature owing to the unsaturated coordination of the surface terminated Ti2O3 rows. Deprotonation of TPA molecules upon adsorption produces both surface bridging hydroxyl (ObH) and bidentate terephthalate species with a saturation coverage of nearly 0.5 monolayers (ML). In contrast to the TiO2(110)-(1 × 1) surface, the band gap states (BGSs) on the bare (1 × 2) surface exhibit an asymmetric spectral feature, which is originated from integrated contributions of the Ti2O3 termination and the defects in the near-surface region. The Ti2O3 originated BGSs are found to be highly sensitive to the TPA adsorption, a phenomenon well reproduced by the density functional theory (DFT) calculations. Theoretical simulations of the adsorption process also suggest that the redistribution of the electronic density on the (1 × 2) reconstructed surface accompanying the hydroxyl formation promotes the disappearance of the Ti2O3-row derived BGS.

Covalent Anchoring and Interfacial Reactions of Adsorbed Porphyrins on Rutile TiO2(110)

“…We therefore fitted the feature as the sum of covalently anchored carboxylate groups (red) and coadsorbed hydroxyl groups (blue) created by the deprotonation of the acid group. The positions of both species agree with those expected for carboxylate and hydroxyl groups , (532.3 and 531.9 eV, respectively). Overall, the O 1s data indicate that the carboxylic acid group has deprotonated and bound covalently to the oxide surface.…”

Identification of Surface Reactivity Descriptor for Transition Metal Oxides in Oxygen Evolution Reaction

“…Therefore, higher [M CUS ] gives rise to higher surface reactivity and this can be evidenced by diminished BGS upon adsorption of oxygen. 21,35 The cases of TiO 2 , α-Fe 2 O 3 , V 2 O 5 , 14,36 and MoO 3 14 can be described well by Figure 6a and b. For stoichiometric p-type TMOs, E d is close to E F and thus antibonding states are partially filled as shown in Figure 6c.…”

Low-Temperature, Solution-Based Sulfurization and Necking of PbS CQD Films

“…This hypothesis is confirmed by examination of the O 1s spectra shown in Figure c,d. Two peaks at 532.3 and 533.8 eV are present in all O 1s spectra and can be, respectively, assigned to oxygen in −COO– (reference value at 532.1 eV) and in −OH (reference value at 533.8 eV) of residual oleic acid. However, the TMS-treated films also exhibit a strong peak at 531.3 eV, which is assigned to PbSO x (reference values of 531 and 531.7 eV for PbSO 3 and PbSO 4 , respectively) .…”