Sensing mechanism of Pd-doped SnO2 sensor for LPG detection

In the present work. studies have been made to analyze the sensitivity, response, recovery time and sensing mechanism of Pd-doped thick film SnO2 sensor for detection of LPG. To achieve this, thick film Pd-doped (0.25 and 1% by weight in available Indium doped SnO2 thick film paste supplied by ESL, USA) along with an undoped (Indium doped) SnO2 sensors were fabricated on a 1 x 1 alumina substrate. It consists of a gas sensitive layer (doped SnO2), a pair of electrodes underneath the gas sensing layer serving as a contact pad for sensor. Also, a heater element on the backside of the substrate was printed for generating appropriate operating temperature at the substrate necessary for acquiring gas sensing properties. The sensor doped with 1% palladium showed the maximum sensitivity of 72% at 350 degrees C for 0.5% concentration of LPG. Possible detailed sensing mechanism of Pd-doped SnO2 sensor for LPG detection has been proposed. (C) 2009 Elsevier Masson SAS. All rights reserved.