Reaction Intermediates in the Photoreduction of Oxygen Molecules at the (101) TiO₂ (Anatase) Surface

Abstract

The structural, electronic, and vibrational properties of intermediates of the O(2) photoreduction at the (101) TiO(2) (anatase) surface have been investigated by performing ab initio density functional calculations. In detail, a recently proposed approach has been used where molecules on the surface are treated like surface defects. Thus, by applying theoretical methods generally used in the physics of semiconductors, we successfully estimate the location and donor/acceptor character of the electronic levels induced by an adsorbed molecule in the TiO(2) energy gap, both crucial for the surface-molecule charge-transfer processes, and investigate the formation and the properties of charged intermediates. The present approach permits a view of the O(2) photoreduction process through several facets, which elucidates the molecule-surface charge-transfer conditions and reveals the key role played by charged intermediates. A comparison of present results with those of a highly sensitive IR (infrared) spectroscopy study of intermediates of the O(2) photoreduction leads to a deeper understanding of this process and to revised vibrational-line assignments and reaction paths.

Unravelling the early oxidation mechanism of zinc phosphide (Zn3P2) surfaces by adsorbed oxygen and water: a first-principles DFT-D3 investigation

“…Prior to the adsorption of O 2 and H 2 O molecules on the Zn 3 P 2 surfaces, the reference energies, bond length (d), and 37 and 1555 cm À1 , 38 as well as with other DFT results. [39][40][41] The d(O-H) and a(HOH) angles of water are calculated to be 0.972 Å and 104.71 respectively, and the calculated asymmetric and symmetric stretching vibrational frequencies are predicted at 3713 and 3623 cm À1 , all of which are in good agreement with experimental values. 42 To characterize the extent of oxidation or reduction of the surface species due to the adsorption of O 2 and H 2 O molecules, Bader charge analysis 44 was performed on all stable adsorbate-surface systems and the results were compared to those of the naked surface counterparts.…”

Probing Defect Sites on TiO2 with [Re3(CO)12H3]: Spectroscopic Characterization of the Surface Species

“…X-ray diffraction (XRD) was used to characterize the asprepared titania sample (designated simply as TiO 2 ) and the treated samples TiO 2ox and TiO 2vac . The XRD pattern of each sample ( Figure 1) includes strong, sharp peaks at 25,38,48,54,55,63,69,70, and 758, matching that of anatase (JCPDS No. .…”

Increasing the Photocatalytic Activity of Anatase TiO2 through B, C, and N Doping

“…Despite these limitations, TiO 2 is nevertheless widely used as a photocatalyst where efficiency and rapid reactions are not critical, such as in self-cleaning and antibacterial surfaces. [15][16][17] The rate of electron transfer to O 2 that is in solution and not adsorbed to the TiO 2 surface is insignificant, and thus the rate of oxygen reduction by photoexcited electrons on the perfect (101) anatase surface is slow. , which subsequently accepts two protons to form H 2 O 2 (hydrogen peroxide) that readily oxidizes the OP.…”