UV and vacuum treatment, as well as annealing, were tried to recover the gas sensing property of WO3 films. Results
show that gas sensing films can partially recover one or two coloring and bleaching cycles if kept in vacuum condition.
And UV irradiation can well recover several cycles. But heat treatment does not show any obvious effect on the gas
sensing recovery. Furthermore, IR and XPS spectra were used to identify the mechanism of this improvement. Results
reveal that changes of water content will reduce the desorption energy of hydrogen atom, which will accelerate the
In this paper, WO<sub>3</sub> sol was prepared via the sol-gel method, and palladium chloride powder was dissolved in the sol in
different W: Pd molar ratios. Pd doped WO<sub>3</sub> films were coated on silicon wafers and ordinary slide glasses by
dip-coating method. The grain distribution of WO<sub>3</sub> sol doped with PdCl<sub>2</sub> was measured by Laser Particle Size Analyzer.
Surface morphology and microstructure of WO<sub>3</sub> films which doped or undoped with PdCl<sub>2</sub> were analyzed by AFM,
which show that PdCl<sub>2</sub> has an important effect on the structure of the WO<sub>3</sub> films. The gasochromic properties of the films
are investigated by UV-Vis spectrophotometer. The WO<sub>3</sub> films show good gasochromic properties. The effect of
concentration of PdCl<sub>2</sub> on gasochromic kinetic process of WO<sub>3</sub> films was investigated. Finally the modulation of the
light transmittance by the gasochromic films was discussed.