Article ID Journal Published Year Pages File Type
744236 Sensors and Actuators B: Chemical 2016 9 Pages PDF
Abstract

•Report the gasochromic effect in hydrothermally synthesized structures for the first time.•Description of the role of H2O molecules in the diffusion process of H atoms using FTIR results.•Introduction of simple methods to enhance the gasochromic effect of WO3 nanoplates such as post-annealing process of samples and adding PdCl2 to activate the WO3 nanoplate's surface.

A hydrothermal method based on ammonium oxalate was developed to grow colloidal suspensions of WO3 flower-like structures at different temperatures. PdCl2 solution was added as a hydrogen catalytic source to the suspensions in order to develop a gasochromic response. Transmission electron microscopy (TEM) revealed the presence of spherical 50–200 nm palladium nanoparticles on the WO3 surfaces. X-ray diffraction patterns (XRD) showed a phase transformation from orthorhombic WO3·(H2O)0.33 to monoclinic WO3 by increasing the hydrothermal growth temperature from 100 to 180 °C. The effect of post-annealing on the WO3 structure was also investigated. Fourier transform infrared spectroscopy (FTIR) was used to identify functional groups, hydroxyl ions and chemical bonds in the WO3. The in-liquid gasochromic effect when a 1:9 hydrogen:argon gas mixture was bubbled through the suspension, showed a color change from clear to blue, with the sample prepared at 150 °C showing the best response. The gasochromic reactions of these hydrothermal samples are compared to those obtained by pulsed laser ablation and anodizing methods.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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