Highly Sensitive and Selective CO/NO/H2/NO2 Gas Sensors Using Noble Metal (Pt, Pd) Decorated MOx (M = Sn, W) Combined With SiO2 Membrane

0.5 mol% Pt decorated SnO2 (Pt-SnO2), 0.5 mol% Pd decorated SnO2 (Pd-SnO2), 0.5 mol% Pt decorated WO3 (Pt-WO3), and 0.5 mol% Pd decorated WO3 (Pd-WO3) gas sensing films were fabricated by screen printing. Subsequently, SiO2 membrane was deposited in situ by CVD. The response of the sensing films to CO, NO, H-2, and NO2 were investigated. Pt- SnO2, Pd-SnO2, and Pt-WO3 with SiO2 membrane deposited for 20 min (Pt-WO3-SiO2) and Pd-WO3 showed highly sensitive and selective to CO, NO, H-2, and NO2 at each optimal operating temperature respectively. Different enhancements of response to target gases might be associated to the combined effects of electronic, chemical sensitizations, and "support effect". The highly sensitive and selective gas sensors in this paper can be integrated into a gas sensor array to fabricate an electronic nose for H-2, CO, NO, and NO2 detection