Influence of Pd-loading on gas sensing characteristics of SnO2 thick films

Abstract Nanocrystalline pristine and 0.5, 1.5 and 3.0 wt% Pd loaded SnO 2 were synthesized by a facile co-precipitation route. These powders were screen-printed on alumina substrates to form thick films to investigate their gas sensing properties. The crystal structure and morphology of different samples were characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. The 3.0 wt% Pd:SnO 2 showed response of 85% toward 100 ppm of LPG at operating temperature of 250 °C with fast response (8 s) and quick recovery time (24 s). The high response toward LPG on Pd loading can be attributed to lowering of crystallite size (9 nm) as well as the role of Pd particles in exhibiting spill-over mechanism on the SnO 2 surface. Also selectivity of 3.0 wt% Pd:SnO 2 toward LPG was confirmed by measuring its response to other reducing gases like acetone (CH 3 COCH 3 ), ethanol (C 2 H 5 OH) and ammonia (NH 3 ) at optimum operating temperature.