SENSORY PROPERTIES OF h-WO DOPED WITH Co AND Fe CATIONS IN RELATION TO TOXIC GASES

The sensory properties of solid solutions of h-CoWO (0 ≤ x ≤ 0.09) and h-WFeO (0 ≤ x ≤ 0.06), as well as m-WO, were studied in relation to various toxic gases at the maximum permissible concentrations in the air. Doping of h-WO with Co or Fe ions does not affect the sensitivity of the sensory response to CHCOCH and NH, but leads to a decrease in the sensory signal relative to NO. A comparative analysis of the sensory properties of tungsten trioxide of hexagonal and monoclinic crystallographic modification has been performed. When detecting CHCOCH and NH, the sensitivity of h-WO is 1.5 and 1.3 times higher than that of m-WO, respectively. The oxygen vacancy concentration and pore volume are key parameters that determine the higher sensitivity of m-WO to NO compared to h-WO.