| The strong metal-support interaction has very important effect on the photocatalytic activity as the system has special electron configuration and geometric structure. So the study of the strong metal-support interaction possesses practical and theoretical interest. With the combination of X-ray photoelectron spectroscopy (XPS) and Ar+ sputtering technique, we investigated the strong metal-support interaction between Pt and TiO2 in different atmosphere, and its effect on the photocatalytic activity of C3H6 was studied.When Pt/TiO2 films were treated by inert N2 at 400℃, the Ar+ sputtering results indicated that with the increase of sputtering time, the binding energy of Pt 4f moved to the higher direction. The higher binding energy of Pt species occurred and at the same time Pt atomic conc. versus sputtering time increased first and then decreased which indicated that two strong interactions occurred: (1) Encapsulation, i.e, The encapsulation of Pt0 particles by TixOy which was formed by the spillover of oxygen atoms from the surface of TiO2 during the high-temperature treatment of Pt/TiO2 in inert N2 gas. (2) Thermal diffusion: Pt0 atoms can diffuse into TiO2 lattice and be oxidized to Pt2+ to substitute for Ti atoms. The experimental results showed that the encapsulation of Pt0 particles by TixOy and the increase of Pt0 particle size were the reasons for the obvious decrease of C3H6 photocatalytic activity.When Pt/TiO2 films were treated in reducing H2 at 400℃, the Ar+ sputtering results indicated that with the increase of sputtering time, the binding energy of Pt 4f moved to the lower direction. The lower binding energy of Pt species occurred and at the same time Pt atomic conc. versus sputtering time increased first and then decreased which indicated that there were two strong interactions occurred (But they were different from those in inert N2 atmosphere): (1) Encapsulation, i.e, during the high-temperature treatment of Pt/TiO2 in reducing H2 gas, the encapsulation of Pt0 particles by TixOy which was formed by the spillover of oxygen atoms from the surface of TiO2. (2) Thermal diffusion: Pt0 atoms can diffuse into TiO2 lattice and be reduced to Pt- to substitute for O atoms. When Pt/TiO2 was treated in reducing H2 at low-temperature 200℃, the PtO layer on the surface of the untreated catalyst transformed to be Pt0 which made the photocatalytic activity increased. But when Pt/TiO2 was treated in reducing H2 at high temperature, the encapsulation and the increase of Pt0 particle size resulted in the decrease of C3H6 photocatalytic activity.In the dissertation the structure and photocatalytic activity of the TiO2 prepared from the treatment of nanotubed titanic acid (NTA) in CO was investigated. The results showed that the TiO2 obtained by CO treatment of NTA were inert in photocatalytic activity under visible-light irradiation, but active under UV-light irradiation, while the UV–light photocatalytic activity decreased with the increase of the treating temperature in CO atmosphere. The characterization results showed that when NTA was treated in CO at high temperature, the carbon doping in product TiO2 did not appear,only carbon deposition on TiO2 appeared; the BET areas of the products decreased markedly with the increase of treating temperature; The transformation temperature from anatase to rutile for TiO2 obtained by CO treatment was much lower than that obtained by air treatment. These were the reasons for the decrease of UV-light photocatalytic activity.
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