Ab Initio Insight into Mechanisms of Ozone Interaction with a Surface of Dehydrated Nanocrystalline TiO₂

Abstract

Density functional theory (DFT) study of ozone adsorption on dehydrated nanocrystalline TiO2 is presented. Singlet and triplet binding modes of ozone to the oxide’s titanium cations are considered. In both the modes, monodentate and bidentate ozone complexes are formed. According to DFT, the triplet monodentates are the most stable species. The formation of monodentate ozone adsorption complexes is in-line with an earlier interpretation of infrared (IR) spectroscopic data on ozone adsorption on an anatase surface. However, the computed difference in the fundamental vibrational frequencies (ν1 – ν3) of ozone in the triplet monodentates is significantly larger than the corresponding IR value. This discrepancy is resolved by demonstrating that the triplet monodentates readily decompose, realizing molecular oxygen that is consistent with published experimental data. The predicted energy barrier of the dissociative adsorption is less than 2 kcal/mol. In contrast, the computed difference in the fundamental vibrational frequencies (ν1 – ν3) of adsorbed ozone in the singlet bidentates perfectly agrees with the experiment.

The Adsorption of Ozone on the Solid Catalyst Surface and the Catalytic Reaction Mechanism for Organic Components

“…In 2020, Kevorkyants and the co‐workers [12h] used DFT to calculate the adsorption of ozone on nanocluster Ti 8 O 16 , shown in Figure 4(A), and they thought that during the adsorption process, the increase of ozone electrophilicity was caused by the capture of electrons from the TiO 2 donor electron sites (probably dicoordinated O 2− ) to produce O 3 − species. The triplet monodentate and the singlet bidentate ozone complexes were the two most stable modes.…”

“… Ball‐and‐stick Model of the Nanocluster Ti 8 O 16 (A) and Fragments of Bidentate and Monodentate Complexes of Ozone with TiO 2 (B) [12h] . Reprinted (adapted) with permission from Ref.…”

“…The main differences of ozonation reaction with the free radical mechanism come from producing free radicals. There were four kinds of ozone adsorption‐decomposition sites and methods reported in the literature: In the first type, after adsorption on the strong Lewis acid sites, ozone molecules decomposed and produced atomic oxygen, hydroxyl radicals, and other oxygen species [11,12f–l] . In the second type, ozone molecules were adsorbed by hydroxyl groups or adsorbed water molecules on the catalyst surface and then decomposed into hydroxyl radicals [12o,13a,c,d,30] .…”

Al@TiO2 Core–Shell Nanoparticles for Plasmonic Photocatalysis

“…TiO 2 -coated surfaces can decompose organic pollutants and can maintain themselves in a pristine state while exposed to irradiation. TiO 2 surfaces facilitate interfacial photochemical reactions, and it has been proposed that these reactions have the potential to change the chemical balance of the atmosphere. − This strong photocatalytic interaction with gas phase molecules motivates the incorporation of TiO 2 into an antenna–reactor photocatalyst complex for gas phase reactions. The photocatalytic activity of TiO 2 is limited by its wide bandgap (3.2 eV) which precludes a significant photoresponse under visible light.…”