Flame-Made Nb-Doped TiO2 Ethanol and Acetone Sensors

Undoped TiO2 and TiO2 nanoparticles doped with 1-5 at.% Nb were successfully produced in a single step by flame spray pyrolysis (FSP). The phase and crystallite size were analyzed by XRD. The BET surface area (SSA(BET)) of the nanoparticles was measured by nitrogen adsorption. The trend of SSA(BET) on the doping samples increased and the BET equivalent particle diameter (d(BET)) (rutile) increased with the higher Nb-doping concentrations while d(BET) (anatase) remained the same. The morphology and accurate size of the primary particles were further investigated by high-resolution transmission electron microscopy (HRTEM). The crystallite sizes of undoped and Nb-doped TiO2 spherical were in the range of 10-20 nm. The sensing films were prepared by spin coating technique. The mixing sample was spin-coated onto the Al2O3 substrates interdigitated with Au electrodes. The gas sensing of acetone (25-400 ppm) was studied at operating temperatures ranging from 300-400 degrees C in dry air, while the gas sensing of ethanol (50-1,000 ppm) was studied at operating temperatures ranging from 250-400 degrees C in dry air.