Gasochromic Response of Pd/NiO Nanostructured Film Towards Hydrogen

The gasochromic performance of nanostructured nickel oxide (NiO) films coated with 25 A catalytic palladium (Pd) layer were investigated for low concentration hydrogen (H(2)) sensing. NiO nanostructures of 20-30 nm sizes were produced via RF sputtering deposition of NiO(x) on quartz substrates and subsequently annealed at 500 degrees C. It was found that the Pd/NiO films show significant gasochromic response when exposed to H(2) at elevated temperatures. Integrating the absorbance change over a range of visible wavelengths (500-800 nm), has enabled very low concentrations of H(2) (0.06%) to be sensed in real time. T(90%) response of 25 angstrom Pd/100 nm NiO film towards 0.06% H(2) in a balance of synthetic air was approximately 120 s at 170 degrees C. Similar H(2) concentration can be recovered in as little as 240 s at 170 degrees C.