Recognition of carbon monoxide with SnO₂/Ti thick-film sensor and its gas-sensing mechanism

We have synthesized undoped and Ti-doped SnO₂ spheres with a facile yet efficient hydrothermal approach and investigated their microstructures and gas sensing response to carbon monoxide, focusing especially on the impact of Ti doping. We find that gas response of SnO₂ is enhanced significantly by doping, the origin of which is clarified in light of a proposed adsorption model. Through a combination of systematic measurements with density-functional-theory calculations, we discuss the enhancement mechanism of the gas-sensing function arising from the doping.