Pd impregnated gallia: tin oxide nanocomposite—An excellent high temperature carbon monoxide sensor

Abstract 1 wt% Pd impregnated gallia: tin oxide nanocomposite sensors were investigated for high temperature carbon monoxide detection. Initially the mixed oxide nanopowder, containing 25 wt% gallia, was synthesised using a facile cost effective sol-gel procedure. 0.25 wt% antimony doping was done to facilitate lower resistance of the corresponding sensor in terms of electronic perspective. The structural and microstructural characterizations of the nanocomposites were carried out with X-ray diffractometer, BET surface area, XPS, TEM and EDX analyses. Taguchi design based thick film sensors were fabricated and CO sensing performance was evaluated in the operating temperature range of 300–500 °C. Nanocomposite sensor showed ∼ 48% optimum response for 30 ppm CO at temperature of 425 °C with stable low resistance. Pd incorporation led to a significant improvement in sensing response (∼65%) at the same condition along with decrease in response and recovery times. Possible sensing mechanism of enhancement has been explored.