Comparative study of the gasochromic performance of Pd/WO3 and Pt/WO3 nanotextured thin films for low concentration hydrogen sensing

The gasochromic performance of WO
₃
nanotextured thin films coated with catalytic Pd or Pt layers were investigated for low concentration H
₂
sensing. The 25¿ thick catalytic metals were deposited onto 200nm thick sputtered WO
₃
films. It was found that the Pd/WO
₃
thin films show superior gasochromic response when compared with Pt/WO
₃
thin films. Integrating the absorbance change over a range of visible wavelengths (500-800nm), has enabled very low concentrations of H
₂
(0.06%) to be easily sensed in real time for both Pd/WO
₃
and Pt/WO
₃
thin films. Pd/WO
₃
T
_90%
response towards 0.06% H
₂
in a balance of synthetic air was 30 seconds at 100°C. Similarly, higher H
₂
concentrations of 1% can be accurately sensed in as little as 20 seconds.