Abstract :
In this paper, the surface states of Pt/TiO2 thin film were tested in air, H2 and N2 flows. Pt/TiO2 was prepared by means of photoreduction
of PtCl2 6 on anatase nano-TiO2 powders and was coated on the microscopy glass using powder–sol technique. Powder conductivity
method was applied in the analysis of surface states. The experimental results show that a new surface state was formed in air
flow; which was 0.43 eV lower than the conduction band edge of TiO2. In N2 flow, three surface states, with the energy levels of 0.42, 0.62
and 0.90 eV, respectively, were detected. Compared with that tested in airflow, 0.42 and 0.62 eV could be attributed to Pt and floating
bond of TiO2 respectively, while 0.90 eV might have resulted from the Ti3+ formed at high temperature in N2 flow. The conductivity of
the sample tested in H2 flow increased significantly and was almost unchanged with temperature, which could be interpreted by the dissociative
adsorption of H2 on Pt.
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