Photoresponse of Pd0/TiO2 film under visible light

PdO/TiO
₂
nanocomposites were prepared by ployol method. TEM, XPS and FSEM were used to observe and measure the microstructure and chemical state of the PdO/TiO
₂
film. In this process, Pd(acac)
₂
was a Pd precursor, ethylene glycol was a reductant, and nano TiO
₂
powder (Degussa P25) was a support, in which the nanopaticles of Pd were highly dispersed on the surface of TiO
₂
. The Pd/TiO
₂
was deposited on the alumina substrate with a comb-like gold electrode, then it was calcined at various temperature in air. XPS shows the Pd on the Pd/TiO
₂
film is in the form of oxide, while FSEM showed that the PdO/TiO
₂
film is porous. The photoconductivity of the PdO/TiO
₂
film is measured under visible light 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/TiO
₂
film is strongly influenced by the sintering temperature. The photoconductivity of the sample sintered at 350degC was higher than that in 550degC. 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.