Cobalt oxide doped hematite as a petrol vapor sensor

Abstract

The study analyzed and interpreted variations in structural, electrical & gas sensing properties of iron oxide (n-type semiconductor) films due to the addition of cobalt oxide (p-type semiconductor). Iron Oxide was synthesized by co-precipitation method. The synthesized iron oxide and readymade cobalt oxide were mechanically mixed in various weight percentages. The screen printing method was used to prepare films. These films were characterized using XRD, SEM, EDS and static gas sensing apparatus. XRD proved the existence of α-Fe2O3 (JCPDS #860550) and cobalt oxide (JCPDS #801543). SEM micrographs demonstrated porous film surface. EDS demonstrated non-stoichiometric elemental distribution in films. Variation in electrical properties (resistivity, TCR, activation energy in high temperature and low-temperature region) were quantitatively and qualitatively discussed. Due to cobalt oxide addition petrol vapor sensitivity and selectivity improved as compared to bare iron oxide films. Co1 films showed 84% sensitivity to petrol vapors at 250 °C. Study tested efficient petrol vapor sensor.