Gas sensing properties of platinum dispersed-TiO2 thin film derived from precursor

Metal-organic precursor solution for coating glass substrates was synthesized using a Ti alkoxide derivative, amino acid, platinum salt and methanol as a solvent. Suitable addition of TiO2 sol remarkably increased the gas sensitivity of the resultant platinum dispersed-TiO2 thin film because of the formation of fine pores around nano-sized TiO2 grains. A thin film fired at 450°C under a reducing atmosphere was not sensitive to reducing gases such as CO and CH4, but revealed high selectivity and sensitivity to H2 at 200°C. This thin film also showed high selectivity to trimethylamine (TMA) and NH3. The selection of an appropriate starting metal-organic precursor and addition of titania sol were very effective in forming the desired microstructure with improved gas sensing properties.