Titanium-doped tungsten oxide for hydrogen sulfide sensors: Synthesis, microstructure and property evaluation
Increasingly strict requirements for environment management of coal-generated waste streams are also anticipated with a growing incentive to reduce CO 2 production through increased efficiency. This planning model imposes demanding requirements for conversion of coal to electricity and to clean gaseous and liquid fuels and, thus, for a strategic program of research, development and commercialization to most efficiently utilize coal resource in the 21 st century. Two very important goals that are proposed with their longer time horizon are increasing emphasis on clean fuels research and on advanced research that addresses the barriers to higher efficiency in both power generation and fuels production to reduce CO2 emissions. Improvements will also be needed in control of air pollutants and the discharge of solid wastes. Our main focus in the present research is to detect the toxic and environmentally important gases that are released from a coal gasifier during the gasification process. Metal oxide semiconductor gas sensors have been victoriously used to measure and monitor trace amounts of environmentally important gases such as CO, NO2, H2S, NH3 and particularly challenging case of CO2. Tungsten oxide (WO3) has been successfully used as a gas sensor to detect very small amounts of gases up to a level of parts per million (ppm). Among the gases released, detection of H 2S, although present in very small amounts in crucial because it is extremely hazardous and toxic compound. In this work, the inhibition of WO 3 crystallization by the addition of Ti in sputter-deposited W 0.95Ti0.05O3 films is observed. The effect of growth-temperature on the crystallization indicates that the W0.95Ti 0.05O3 films grown at temperatures <300 >°C are amorphous compared to WO3 crystalline films at 100-200 °C. Phase transformation is induced in W0.95Ti0.05O3 resulting in tetragonal structure at ≥300 °C.
Kalidindi, Narasimha Raju, "Titanium-doped tungsten oxide for hydrogen sulfide sensors: Synthesis, microstructure and property evaluation" (2010). ETD Collection for University of Texas, El Paso. AAI1483869.