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

The gasochromic performance of WO₃ nanotextured thin films coated with catalytic Pd or Pt layers were investigated for low concentration H₂ sensing. The 25¿ thick catalytic metals were deposited onto 200nm thick sputtered WO₃ films. It was found that the Pd/WO₃ thin films show superior gasochromic response when compared with Pt/WO₃ thin films. Integrating the absorbance change over a range of visible wavelengths (500-800nm), has enabled very low concentrations of H₂ (0.06%) to be easily sensed in real time for both Pd/WO₃ and Pt/WO₃ thin films. Pd/WO₃ T_90% response towards 0.06% H₂ in a balance of synthetic air was 30 seconds at 100°C. Similarly, higher H₂ concentrations of 1% can be accurately sensed in as little as 20 seconds.