Synergistic effect of tungsten on gas sensing characteristics of chromium oxide based gas sensor

Enhancement of gas sensing response due to addition of tungsten into Cr2O3 has been reported. Pure and W-doped Cr2O3 nanoparticles, prepared by a chemical method, have been characterized by X-ray diffraction and field emission scanning electron microscopy. X-ray diffraction studies have revealed the substitution of Cr3+ ions by W6+ ions. The concentration of tungsten, used as dopant, has been varied from 1 to 5 wt% and its effect on structural and gas sensing properties has been studied. Synthesized samples have been deposited as a thick film onto alumina substrate and tested for methanol, ethanol and propanol at different operating temperatures. All the sensors have exhibited optimum response at 250 °C. Fabricated sensors have exhibited best response towards propanol vapour. The activation energy of conduction for all the samples has been estimated using Arrhenius plots and it has been observed that sample doped with 3 wt% W possesses minimum activation energy and interestingly this sample gives the best sensing response amongst fabricated sensors.