Preparation and Photocatalytic Reaction of Pt-modified TiO2:From Liquid Phase to Gas Phase

• Main Authors: Bo-Hao You, 游泊皓
• Other Authors: 蘇昭瑾
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/a9pp4f

碩士 === 國立臺北科技大學 === 有機高分子研究所 === 93 === The purpose of this work is to prepare powdered Pt/TiO2 with various Pt-content and to study their photocatalytic activity in decomposition of organic molecules. The Pt/TiO2 samples were prepared by depositing Pt on Degussa P25 TiO2 powders through photoreduction of aqueous hexachloroplatinate(IV) acid. The characterization of as-prepared Pt/TiO2 was performed using the combination techniques of Electron Spectroscopy for Chemical Analyzer (ESCA), Transmission Electron Microscope (TEM), Energy Dispersive Spectrometer (EDS), X-Ray Diffractometer (XRD), and Brunauer-Emmett-Teller (BET). Deposition of Pt leads to the shift of Ti (2P) and O (1s) ESCA peaks to low binding energy side for Pt content up to 4 %. Simultaneously, the of Pt (4f) ESCA peak shifts to high binding energy side for Pt content up to 2 %. The result was explained by Ti4+-induced surface polarization with partial negative charge on the TiO2 substrate. The TEM micrographs indicate that the deposition of platinum can cause agglomeration of TiO2 particles. To verify the effect of Pt content on the photocatalytic activity of the Pt/TiO2, the experiments of degradation of methylene blue (MB) in aqueous solution and the photooxidation of methyl iodide in gas phase were carried out. The Pt/TiO2 sample containing 2.12 % Pt showed the consistently best photocatalytic activity for both systems. The addition of Pt on TiO2 also changed the reaction pathway for CH3I decomposition upon irradiation. Possible correlation between the Pt content and photocatalytic property of Pt/TiO2 is discussed in the thesis.