Photoinduced Dynamics of Radicals in N- and Nb-Codoped Titania Nanocrystals with Enhanced Photocatalysis: Experiment and Modeling

Abstract

Titanium dioxide (TiO2) nanocrystals are one of the most promising materials for modern photocatalysis applications, having unique properties such as a huge specific surface area and affordability of synthesis. However, the facile fabrication of TiO2-based photocatalysts active in regular daylight remains a major challenge. In this work, aiming to create such a nanocrystalline material by a very simple technology, we provide a detailed analysis of the paramagnetic centers (PCs) and their photoinduced reactions in N- and Nb-codoped TiO2 nanocrystals. The resulting powders show a surface area up to 170 m2/g and an intense visible-light photocatalysis of rhodamine 6G with reaction rate k = 0.087 min–1. Ti3+, N•, and O2 – PCs are observed and studied using electron paramagnetic resonance spectroscopy. We also present a new approach to the study of photoinduced processes in nanocrystalline photocatalystsa simple theoretical model of kinetics of these PCs, which well predicts their behavior and variations of their concentration under illumination. Our results indicate that the obtained Nb–N–TiO2 nanocrystals with a high concentration of PCs on the sample surface can be used in cutting-edge industries, paving the way for the most advanced photocatalytic systems operating in sunlight.

A Critical Review of the Photocatalytic Degradation of Pharmaceutical Residues by a TiO2-Based Photocatalyst

“…Quantum efficiency measurements: Quantum efficiency measurements provide insights into the The principal origins of antibiotics found in water systems efficiency of TiO2 in converting absorbed photons into photocatalytic reactions. This method involves measuring the amount of photons absorbed and the number of reactive species generated [33]. This information helps to evaluate the overall performance of TiO2 photocatalysts.…”

Strategy for Patterning Titania Dendrites by Gas–Solution Interaction at Droplet Surfaces

“…Earlier, it was reported about obtaining ordered honeycomb-like manganese oxide structures on the surface of a drop of aqueous solution of manganese acetate under the action of gaseous ozone. , The object selected for the present research is the hydrated titanium dioxide formation reaction resulting from hydrolysis occurring on the surface of a drop of the titanium salt aqueous solution under the action of ammonia vapor in air. Titania has a range of promising multifunctional properties and a wide variety of applications in the creation of pigments, sorbents, catalysts, optically and photochemically active materials, − sensors, bactericidal and smart , coatings, etc. Common methods for obtaining titania microspheres include hydrolysis between titanium alkoxide and water droplets in a microfluidic reactor or thermally assisted hydrolysis of TiCl 4 vapors by water-based aerosol .…”

Structural Diversity Design, Four Nucleation Methods Growth and Mechanism of 3D Hollow Box TiO2 Nanocrystals with a Temperature-Controlled High (001) Crystal Facets Exposure Ratio

“…Photocatalysis is a commonly used method to address environmental pollution and energy scarcity issues. TiO 2 is the most widely used photocatalytic material due to its high chemical stability, , high degree of commercialization, , and excellent catalytic performance. , However, TiO 2 has low solar energy utilization and a high electron–hole recombination rate, indicating that the catalytic performance of TiO 2 still needs to be improved. Generally, anatase TiO 2 has better photocatalytic activity. − Zhu et al used TiCl 4 and benzyl alcohol to carry out a nonhydrolytic sol–gel reaction at low temperature to prepare anatase TiO 2 nanoparticles, which have a much higher degradation effect on phenol than P25 .…”

“…Photocatalysis is a commonly used method to address environmental pollution and energy scarcity issues. TiO 2 is the most widely used photocatalytic material due to its high chemical stability, 9,10 high degree of commercialization, 11,12 and excellent catalytic performance. 13,14 However, TiO 2 has low solar energy utilization and a high electron−hole recombination rate, indicating that the catalytic performance of TiO 2 still needs to be improved.…”