Preparation And Photocatalytic Performance Of Tio₂ And Pt/tio₂ Nano Composite Photocatalyst Based On Thermocatalytic Synergetic Effect

Nanostructured TiO2 as a cheap, non-toxic, efficient photocatalyst is one of the most promising materials for water purification. When used with Nanostructured TiO2 as photocatalyst volatile organic compounds (VOC) catalytic purification, photodegradation in process, there are many difficult degradable intermediate product adsorption in the photocatalyst surface, which make catalyst quick deactivation. Therefore, how to improve its photocatalytic stability and to further enhance its Photocatalytic Activity is still one of the most important tasks in the field of photocataly now.In this paper, the TiO2 and Pt/TiO2 photocataly are prepared. They are characterized with XRD, Raman, BET, TEM, DRUV-vis, and photoelectrochemical measurement. under the photothermocatalytic, thermocatalytic and photocatalytic condition, The catalyst for VOC of catalytic degradation performance are researched. The main contents of this dissertation are listed as follows:1) Structural reconstruction of TiO2 (P25), which is widely used as a benchmarking photocatalyst, was achieved by ball milling followed by calcination at 400℃. It was found that the reconstruction leads to a considerable enhancement in its photocatalytic activity both for the photodegradation of aqueous dye solution and for the gas-phase photodegradation of benzene. The enhancement is due to the formation of more rutile/anatase phase heterojunctions, which significantly promotes the separation efficiency of photo generated electrons and holes.2) The catalysts with high efficient photothermocatalytic oxidation of benzene exhibits much higher efficiency and stability for the detoxification of benzene compared with the photocatalytic and thermocatalytic oxidation of benzene on Pt/TiO2. the catalytic oxidation's mechanism of benzene on Pt/TiO2 follows:1) Under the photothermocatalytic conditions, Benzene is first oxidized by the lattice oxygen in TiO2 catalyst, and then the reduced TiO2-x catalyst is re-oxidized later by gaseous oxygen. The much higher efficiency of the photothermocatalytic oxidation than the combination of both photocatalytic and thermocatalytic oxidation of benzene is attributed to the existence of a photothermocatalytic synergetic effect, which greatly decreases the activation energy of benzene oxidation by the lattice oxygen in TiO2.2) oxygen (O2) dissociatively adsorbs onto Pt nano particles to give surface O(Os) adatoms while oxygen adsorption over pure TiO2 is molecular. There is a spillover of the Os adatoms from Pt nano particles to the surface of support (e.g.TiO2). Under the thermocatalytic condition, the spillover Os adatoms oxidize benzene and the reduced TiOx catalyst to CO2 and TiO2, respectively, which results in the efficient thermocatalytic oxidation of benzene.