Recent Advancements in the Understanding of the Surface Chemistry in TiO2 Photocatalysis

Abstract

Surface chemistry plays a major role in photocatalytic and photoelectrochemical processes taking place with the participation of TiO2. The synthesis methods, surface characterizations, theoretical research methods, and hardware over the last decade generated opportunities for progress in the surface science of this photocatalyst. Very recently, attention was paid to the design of photocatalysts at the nanoscale level by adjusting the types of exposed surfaces and their ratio, the composition and the surface structure of nanoparticles, and that of individual surfaces. The current theoretical methods provide highly detailed designs that can be embodied experimentally. The present review article describes the progress in the surface science of TiO2 and TiO2-based photocatalysts obtained over the last three years. Such aspects including the properties of macro- and nano-scale surfaces, noble-metal-loaded surfaces, doping with Mg and S, intrinsic defects (oxygen vacancies), adsorption, and photoreactions are considered. The main focus of the article is on the anatase phase of TiO2.

Laser Desorption/Ionization Mass Spectrometry as a Potential Tool for Evaluation of Hydroxylation Degree of Various Types of Titanium Dioxide Materials

“…In other words, in our experiments, the (TiO 2 ) n − ions formed under LIFT conditions are very reactive towards gas-phase water impurities, in contrast to the (TiO 2 ) n − ions produced in the LDI source. It must be added that our results are not contrary to those reported in [23,34], which have been obtained in different conditions (e.g., with respect to the reaction time). On the other hand, it indicates that the behavior of the gas-phase titanium oxide cluster is very sensitive to the conditions used.…”

“…Figure 3 shows the breakdown plots of the (TiO2)3OH − /(TiO2)nOH − ratio against the n number ((TiO2)3OH − is an abundant ion at m/z 257, (the ions TiO2OH − The heating of TiO 2 affects not only the hydroxylation degree, but also a number of other surface parameters, e.g., surface area, pore-volume, surface morphology, oxygen and titanium vacancies, surface roughness, surface micro-topography, etc. [30][31][32][33][34]. These parameters have a minor influence on the FTIR spectra, but may significantly affect the LDI mass spectra (which is easy to justify).…”

Photocatalytic treatment based on TiO2 for a coal mining drainage

“…However, the presence of photocatalysts in the reaction medium did lead to a decrease in the concentration of anions in the fluid phase. The addition of sulfate ions on the surface of TiO2 prepared in the laboratory is a viable alternative for modifying the surface properties of this oxide, given the effectiveness of the adsorption of these ions on its surface [30][31][32]. The photocatalytic treatment also allows the removal of sulfates and sulfides from the coal mining drainage, which remained adsorbed on the surface of the TiO2.…”

Improving Thermal Stability and Hydrophobicity of Rutile-TiO2 Nanoparticles for Oil-Impregnated Paper Application

“…Rutile-TiO 2 has a relatively high dielectric constant, making it suitable for some dielectric applications [31][32][33][34][35][36][37]. Although TiO 2 NPs are an attractive nanofiller for kraft paper, it has a major weakness in being hydrophilic [7,38,39]. It is worth noting that in the literature, most studies on modifying kraft paper with TiO 2 have been with the anatase phase and not the rutile.…”