Selective Oxidation Using Flame Aerosol Synthesized Iron and Vanadium-Doped Nano-TiO₂

Abstract

Selective photocatalytic oxidation of 1-phenyl ethanol to acetophenone using titanium dioxide (TiO 2 ) raw and doped with Fe or V, prepared by flame aerosol deposition method, was investigated. The effects of metal doping on crystal phase and morphology of the synthesized nanostructured TiO 2 were analyzed using XRD, TEM, Raman spectroscopy, and BET nitrogen adsorbed surface area measurement. The increase in the concentration of V and Fe reduced the crystalline structure and the anatase-to-rutile ratios of the synthesized TiO 2 . Synthesized TiO 2 became fine amorphous powder as the Fe and V concentrations were increased to 3 and 5%, respectively. Doping V and Fe to TiO 2 synthesized by the flame aerosol increased photocatalytic activity by 6 folds and 2.5 folds, respectively, compared to that of pure TiO 2 . It was found that an optimal doping concentration for Fe and V were 0.5% and 3%, respectively. The type and concentration of the metal dopants and the method used to add the dopant to the TiO 2 are critical parameters for enhancing the activity of the resulting photocatalyst. The effects of solvents on the photocatalytic reaction were also investigated by using both water and acetonitrile as the reaction medium.

Vanadium-doped TiO2 anatase nanostructures: the role of V in solid solution formation and its effect on the optical properties

“…Extensive research has been made in order to modify the band gap of TiO 2 anatase nanostructures to absorb wavelengths longer than 387 nm (3.2 eV) by introducing metal or nonmetal dopants. 6,7,9,10,[12][13][14][15][16][17][18] In this way, vanadium-doped TiO 2 can show suitable characteristics for its application as a photocatalyst and different synthesis methods have been proposed to achieve this goal. 7,[14][15][16] Technological applications of nanostructured materials are directly related to several factors such as the morphology, size, crystalline phase and activity of a specific crystalline plane.…”

Nanotubular Pt-loaded TiO2 catalysts with vanadium-doping to enhance water–gas shift reaction activity

“…This result can be attributed to the influence of metal doping on the surface energy of the oxide, which effectively suppresses particle growth to a smaller size. 42,43 In addition, the tendency for a high surface area is maintained even after Pt-loading.…”

Critical design of heterogeneous catalysts for biomass valorization: current thrust and emerging prospects

“…83 The incorporated SiO 2 increases the proton density that effectively promotes the decomposition of the formed surface peroxide-Ti species, Scheme 3 Photocatalytic oxidation of 1-phenyl ethanol to acetophenone over TiO 2 (□ = surface hole). 51 Catalysis Science & Technology Minireview leading to catalyst surface site regeneration. As a result, an about two-fold improvement in conversion was achieved when a small quantity of SiO 2 was incorporated into TiO 2 after the pre-treatment with acid to afford more Brønsted acid sites.…”

“…The proposed mechanism of this reaction is initiated with the interaction of a surface hole (of catalyst) with the hydroxyl group of the alcohol, forming metaloxo species with proton removal (Scheme 3). 51 Alcohols with long carbon chains and branching are the most suitable substrates that make the proton removal step easier. Furthermore, a higher number of adjacent hydrogen atoms is also a key factor for the simpler removal of proton to achieve an improved conversion rate.…”