Gas Sensitivity of Sol-gel Prepared Mesoporous WO3 thin Film

Tungsten oxide thin film was prepared by sol-gel method from tungsten hexachloride (WCl6) precursor material in analytical grade ethanol. In order to form the porous nanostructured WO3 thin film Pluronic F127 was added to the solution. The sol-gel solution was deposited by spin coating on micro-hotplates containing interdigital platinum electrodes on top to measure the sensing layer conductivity. The porous tungsten oxide films were sensitized with ∼20nm platinum nanoparticles. Sensor responses of pure and sensitized porous WO3 were measured and their responses for 100ppm H2S in synthetic air were compared in the 140-260̊C operation temperature range. The presence of platinum nanoparticles significantly increased the sensitivity for H2S gas. Test results of different operating temperatures were investigated in terms of sensitivity, stability and response time.