Nano ceria as xylene sensor - Role of cerium precursor

Cerium oxide (CeO2) thin films were deposited on glass substrates by spray pyrolysis technique using three different precursors namely cerium chloride heptahydrate, cerium nitrate hexahydrate and cerium acetate hydrate. Structural, morphological, optical, electrical and sensing properties of the CeO2 thin films were examined. X-ray diffraction patterns of spray deposited CeO2 thin films confirmed the formation of polycrystalline cubic fluorite crystal structure. The surface morphologies of CeO2 films were observed using field emission scanning electron microscope. The optical band gap observed from luminescence spectra varied from 3.23 to 3.57 eV. Room temperature sensing characteristics of CeO2 thin films towards acetone, ethanol, xylene and toluene were observed. CeO2 thin film deposited using cerium acetate hydrate at 0.1 M concentration exhibited a better response towards xylene with fast response and recovery times of 224 and 13 s respectively at ambient temperature.