Photoresponse of PdO/TiO2 film under visible light

PdO/TiO2 nanocomposites were prepared by ployol method. TEM, XPS and FSEM were used to observe and measure the microstructure and chemical state of the PdO/TiO2 film. In this process, Pd(acac)(2) was a Pd precursor, ethylene glycol was a reductant, and nano TiO2 powder (Degussa P25) was a support, in which the nanopaticles of Pd were highly dispersed on the surface of TiO2. The Pd/TiO2 was deposited on the alumina substrate with a comb-like gold electrode, then it was calcined at various temperature in air. XPS shows the I'd on the Pd/TiO2 film is in the form of oxide, while FSEM showed that the PdO/TiO2 film is porous. The photoconductivity of the PdO/TiO2 film is measured under visible fight in room temperature in pure N-2 or N-2 doped with 1000 ppm O-2 respectively. The results show that, in pure N-2, the photoconductivity of the PdO/TiO2 film is strongly influenced by the sintering temperature. The photoconductivity of the sample sintered at 350 degrees C was higher than that in 550 degrees C. The photoconductivity of the film is also influenced by trace O-2 in N-2. Under continuous light irradiation, the photoconductivity of the film is responded to the doping of O-2 in N-2, which could decrease the photoconductivity remarkably. By this phenomenon, it is suggested that a trace oxygen sensor can be developed, which can work in room temperature.