Hydrogen sensing performance of gas-chromic WO3/ZnO sol-gel films

The growing interest in the unique physico-chemical properties of hydrogen extends beyond the contemporary era, where the element plays a crucial role in significant industrial processes like ammonia synthesis. In fact, in the future hydrogen could be the key source of renewable energy. Despite its widespread use in current society, there is a pressing need to develop efficient sensors to monitor and control gas concentration. In this context, this thesis project is focused on the fabrication of the sensitive component of an optical gas sensor. More specifically, nanometric gas-chromic films composed of WO3 and ZnO are synthesized using the sol-gel technique. The sensitive films are deposited via spin-coating on fused silica glass substrates, thermal treated at 550°C, and coated with platinum nanoparticles as catalysts. The influence of ZnO content on the gas-chromic activity of WO3 was evaluated by monitoring the variation in absorbance at 870 nm when exposed to hydrogen gas at different operating temperatures (20°C, 100°C, 200°C) and for various concentrations of the target gas.