Low-temperature chemical fabrication of WO3 gasochromic switchable films: a comparative study of Pd and Pt nanoparticles dispersed WO3 films based on their structural and chemical properties

Pd nanoparticles dispersed WO3 (Pd-WO3) gasochromic switchable films were prepared using our method combining UV irradiation and H2 gas flow at room temperature. Structural, chemical and optical switching properties of the films were evaluated and compared with those of the Pt-WO3 films prepared using the same method. It was found that the distribution of catalysts in the Pd-WO3 films was different from that in the Pt-WO3 films. The Pd-WO3 films exhibited large difference in optical transmittance in their colored and bleached states, which was similar to that of the Pt-WO3 films. However, the coloring of the Pd-WO3 films by H2 gas was a little slower than that of the Pt-WO3 films, although the bleaching of these films by air was similarly fast. It was speculated that the difference in the gasochromic properties between the Pd-WO3 and the Pt-WO3 films is likely due to the difference in the distributions of catalysts between the Pd-WO3 and the Pt-WO3 films.