Role of point defects on the reactivity of reconstructed anatase titanium dioxide (001) surface

Abstract

The chemical reactivity of different surfaces of titanium dioxide (TiO2) has been the subject of extensive studies in recent decades. The anatase TiO2(001) and its (1 × 4) reconstructed surfaces were theoretically considered to be the most reactive and have been heavily pursued by synthetic chemists. However, the lack of direct experimental verification or determination of the active sites on these surfaces has caused controversy and debate. Here we report a systematic study on an anatase TiO2(001)-(1 × 4) surface by means of microscopic and spectroscopic techniques in combination with first-principles calculations. Two types of intrinsic point defects are identified, among which only the Ti3+ defect site on the reduced surface demonstrates considerable chemical activity. The perfect surface itself can be fully oxidized, but shows no obvious activity. Our findings suggest that the reactivity of the anatase TiO2(001) surface should depend on its reduction status, similar to that of rutile TiO2 surfaces.

Oxygen vacancy related distortions in rutileTiO2nanoparticles: A combined experimental and theoretical study

“…4(a)] correspond to contributions of hybridized Ti(3d)-O(2p) states at the VB. Defect states at about 0.8 eV below the E F , related to occupied Ti(3d) orbitals, confirm the presence of oxygen defects in our samples [23,43,44]. Locations of the peaks corresponding to the e g and t 2g states in CB, determined from DFT calculations, are in agreement with those established experimentally from the O K-edge spectrum.…”

Activation and Enhancement of Room-Temperature Ferromagnetism in Cu-Doped Anatase TiO2 Films by Bound Magnetic Polaron and Oxygen Defects

“…It is briefly outlined that the Ti 2p 3/2 peak of Sample A30-1 and A0-1 was broader at lower binding energy than that of the TiO 2 films reported by previous work. [25][26] As proposed by Wang et al, 27 the broadening of Ti 2p 3/2 peak at low binding energy could be ascribed to the appearance of Ti 3+ or Ti 2+ . After performing the deconvolution with Lorentzian-Gaussian distribution function, the Ti 2p 3/2 spectrum of Sample A0-1 displayed two peaks at 459.2 and 457.6 eV, which are assigned to Ti 4+ and Ti 3+ .…”

Atomic Defects in Titanium Dioxide

“…Furthermore, the BGSs of the (101) and (001) surfaces of anatase TiO2 have been observed at approximately 1.0 eV. [115,116] Interestingly, Moser et al observed dispersive behavior of the defect states at 0.1 eV on anatase (001) that is different from rutile using ARPES, [117] suggesting that the behaviors of the BGSs on the anatase and rutile TiO2 surfaces are different. The characteristic nature of the atomic defects on the other facets of rutile TiO2 and anatase TiO2 need to be investigated.…”