The aim of this project was to engineer the materials studied to enhance the so-called 3S criteria: Sensitivity, Selectivity, and Stability, by using the advantage of controlling structure and properties at nanometer dimensions. It targeted sensor materials that are able to detect poisonous gases resulting from coal-gasification processes, especially sulfur containing emissions. Research findings based on this award demonstrate that doping tungsten oxide (WO{sub 3}) with a small amount of Ti (e.g. 5% in our work) results in a new material that has a higher structural symmetry (e.g. tetragonal morphology) as well as narrower crystalline particle size distribution. As high quality materials with excellent ordered structure and narrower particle-size distributions (which can also withstand high-temperature technological environments such as those encountered in furnaces and coal gasification systems without their structure being affected by phase transformations) are needed for developing new, more sensitive sensor materials, W-Ti-O thin films grown by RF sputtering are valuable candidates for such roles. It is well known that pure WO{sub 3} will change its structure at elevated temperatures. Our work indicates that, Ti doping not only increases the stability of the resultant material by promoting structural phase modifications, but also increases its sensitivity by increasing the …