Highly selective hydrogen sensing of Pt-loaded WO3 synthesized by hydrothermal/impregnation methods

Unloaded and 0.25–1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by hydrothermal method using sodium tungstate dihydrate and sodium chloride as precursors in an acidic condition and impregnated using platinum acetylacetonate. Pt-loaded WO3 films on an Al2O3 substrate with interdigitated Au electrodes were prepared by spin-coating technique. The response of WO3 sensors with different Pt-loading concentrations was tested towards 0.01–1.0 vol% of H2 in air as a function of operating temperature (200–350 °C). The 1.0 wt% Pt-loaded WO3 sensing film showed the highest response of ∼2.16 × 104 to 1.0 vol% H2 at 250 °C. Therefore, an operating temperature of 250 °C was optimal for H2 detection. The responses of 1.0 wt% Pt-loaded WO3 sensing film to other flammable gases, including C2H5OH, C2H4 and CO, were considerably less, demonstrating Pt-loaded WO3 sensing film to be highly selective to H2.