Pt and Pd as catalyst deposited by hydrogen reduction of metal salts on WO3 films for gasochromic application

In this study, tungsten oxide films were deposited by pulsed-laser deposition (PLD) technique. The as-deposited films were annealed at 250 °C in air for 1 h. The surface morphology, microstructure, crystalline phase, and chemical composition of the films were characterized by SEM, XRD and XPS techniques. Pt nanoparticles were deposited onto the tungsten oxide films through a two-step process. First of all, a layer of PtCl2 was coated on the WO3 surface by drop-drying the PtCl2 solution onto the WO3 surface at 60 °C. Consequently, the reduction of the PtCl2 into the metallic Pt nanoparticles was performed at 200 °C. In this study, the effect of the temperature during hydrogen reduction of PtCl2 as well as the influence of operating temperature on the gasochromic performance of Pt–WO3 samples were investigated. Results revealed that the gasochromic responses of the Pt–WO3 samples have attained approximately a constant value at temperatures above 90 °C. On the other hand, their responses are insignificant at temperatures below 90 °C. Additionally, for the sake of comparison, some results of the gasochromic performance of Pd-WO3 films were presented.