Study On Preparation And Ethanol Gas-sensing Properties Of Sb-doped TiO₂Micro-nanomaterials

Abstract:Due to its wide bandgap of3.0eV(rutile) and3.2eV(anatase), TiO2gas sensor show a high resistance and poor sensitive performance, which limit its further application. In this paper, TiO2with high sensitive is fabricated by morphology control and doping, which not only reduces the resistance but also reduces the working temperature. The main contexts are as follows:(1) Sb-doped TiO2nanobelts were prepared by a simple alkaline hydrothermal process. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM). All of the samples are anatase and the nanobelts are about5-10μm in length and100-300nm in width. Compared with the undoped TiO2nanobelts, Sb-doped TiO2nanobelts show an enhancement of the sensors sensitivity, as well as a decrease of the optimal working temperature from400℃to300℃. The optimum Sb doping amount of TiO2nanobelts for ethanol sensing was7.5mol%. The7.5mol%doped TiO2nanobelts sample shows the highest response with a value of13.82and the response and recovery times to100ppm ethanol were19s and11s respectively. Moreover, the low detection limit of ethanol was estimated to be bellow lppm.(2)3D TiO2microspheres with three different building blocks morphologies were prepared by a simple alkaline hydrothermal process. The samples were characterized by X-ray powder diffraction (XRD), Scanning electron microscope (SEM). All of the samples are made up of3D microspheres, and the diameter of the microspheres is around2-4μm. The samples with3D microspheres nanostructures composed of nanoparticles are rutile, The samples with3D microspheres nanostructures composed of nanorod or nanobelts are the mixture phases of rutile and brookite. The samples with3D microspheres nanostructures composed of nanoparticles show the highest response with a value of72.45and the response and recovery times to100ppm ethanol were23s and8s respectively at the work temperture of350℃. Moreover, the low detection limit of ethanol was estimated to be bellow10ppm. (3) Sb-doped3D microspheres TiO2nanostructures were prepared by a simple acid hydrothermal process. The samples were characterized by X-ray powder diffraction (XRD), Scanning electron microscope (SEM). All of the samples are rutile, and the Sb-doped3D microspheres nanostructures composed of nanorods with a lengh of about1μm. Sb-doped3D microspheres show a decrease of the optimal working temperature from350℃to200℃. The optimum Sb doping amount of3D microspheres composed of nanorods for ethanol detection was7.5mol%. The7.5mol%doped3D microspheres composed of nanorods sample show the highest response with a value of11.82and the response and recovery times to100ppm ethanol were23s and8s respectively. Moreover, the detection limit of ethanol was estimated to be bellow10ppm.