Photooxidation of Trichloroethylene on Pt/TiO₂

Abstract

The gas-phase photooxidation of trichloroethylene (TCE) on Pt/TiO2 has been investigated. The wavelength dependence of this reaction on Pt/TiO2 shows that the addition of small amounts of platinum (≤2%) to TiO2 can enhance the photooxidation of TCE to much longer wavelengths. This result correlates with Maxwell−Garnett calculations and experimental absorption curves for Pt/TiO2 samples. Although the spectral response of Pt/TiO2 extends to longer wavelengths, Pt/TiO2 is found to be less effective in the photooxidation of gas-phase TCE upon broad-band irradiation (λ > 300 nm) compared to TiO2. It is proposed that site blocking by the Pt particles of the most active sites, Ti3+ sites, is the cause of the decreased photoactivity. In addition, it has also been determined that the photoproduct distribution changes as a function of platinum loading. Mechanisms to explain the observed effects of Pt loading on the photooxidation of TCE on Pt/TiO2 are discussed.

Singlet oxygen photogeneration and 2,4,6-TCP photodegradation at Pt/TiO2 under visible light illumination

“…Similar absorption spectra for Pt-TiO 2 were obtained and discussed in other work. 19,20 Belloni et al reported that the absorption properties of platinized TiO 2 depend on the optical properties of the metal, the matrix and the volume fraction of the metal in the nanocomposite. 19 In their work, the absorption in the visible region of Pt-TiO 2 , with 1% Pt, reached more than 30% of the intensity at the maximum.…”

A review on plasmonic metal⿿TiO2 composite for generation, trapping, storing and dynamic vectorial transfer of photogenerated electrons across the Schottky junction in a photocatalytic system

“…It was proposed that the defect sites (Ti 3+ ) which are necessary for the oxidation of CO to CO 2 was preferentially blocked by Pt particles which reduces the photoreactivity of the catalyst. Pt deposited TiO 2 is also reported to be less effective in the photooxidation of gasphase TCE under broad-band irradiation ( > 300 nm) compared to TiO 2 [53]. [56].…”

Ag/AgBr/TiO2 Visible Light Photocatalyst for Destruction of Azodyes and Bacteria

“…[1][2][3][4][5] The main drawbacks of low quantum yields and the lack of visible light utilization, however, hinder its practical application. To handle these problems, numerous studies have recently been performed to enhance the photocatalytic efficiency and visible light utilization of TiO 2 , which include impurity doping, [6][7][8][9] metallization, [10][11][12][13][14][15] and sensitization. 16,17 According to these published works, the deposition of the metal on visible light catalysts highly improved its photoefficiency through the Schottky barrier CB electron trapping and consequent longer electron-hole pair lifetimes.…”