Photocatalytic properties of mesoporous TiO2/ZrO2 films in gas-phase oxidation of alcohols

Abstract

We have used the sol-gel template synthesis method to obtain mesoporous zirconium-containing titanium dioxide films and have studied their structural and sorption characteristics, surface acid function, and photocatalytic activity during gas-phase oxidation of aliphatic alcohols. We have shown that the zirconium content changes the acidity and specific surface area of the films, determining the rate at which the studied processes occur and the relative yield of reaction products.The high activity of titanium dioxide as a photocatalyst of redox conversions for a broad range of organic and inorganic substrates, coupled with its resistance to corrosion and low toxicity, is why there is interest in searching for and developing new methods for synthesis of materials based on TiO 2 having a certain phase composition and texture [1,2]. Development of template synthesis methods has made it possible to obtain powders and films of TiO 2 with an extended surface area and a porous structure [3,4], which is especially important for carrying out photocatalytic oxidation of volatile organic compounds, in particular ethylene [5], acetone [6], and ethanol [2,7,8], which are potential air pollutants at industrial sites. An effective method for increasing the photocatalytic activity of titanium dioxide is also incorporation of transition metal and noble metal ions into a titanium dioxide matrix [9]. Such doping leads to improvement of the texture properties of TiO 2 , an increase in the acidity of its surface, acceleration of phase transfer, and an increase in the degree of separation of photogenerated charges. According to [5], silicon and zirconium-containing mixed oxides based on titanium dioxide are characterized by the most acidic surface. In this case, the increase in photocatalytic activity of TiO 2 /SiO 2 and TiO 2 /ZrO 2 compared with pure TiO 2 is connected with the increase in thermal stability of the porous structure and the increase in the acidity of the surface [6], and also with generation of structural defects due to incorporation of impurity ions into the titanium dioxide lattice [10].This work was devoted to the study of the effect of a zirconium oxide additive on the phase composition of mesoporous TiO 2 films synthesized by the sol-gel template method, their structural and sorption properties, surface acidity, and catalytic activity during gas-phase photocatalytic oxidation of aliphatic alcohols.