Enhanced NH 3 and H 2 gas sensing with H 2 S gas interference using multilayer SnO 2 /Pt/WO 3 nanofilms.

The selective detection and classification of NH and HS gases with HS gas interference based on conventional SnO thin film sensors is still the main problem. In this work, three layers of SnO/Pt/WO nanofilms with different WO thicknesses (50, 80, 140, and 260 nm) were fabricated using the sputtering technique. The WO top layer were used as a gas filter to further improve the selectivity of sensors. The effect of WO thickness on the (NH, H, and HS) gas-sensing properties of the sensors was investigated. At the optimal WO thickness of 140 nm, the gas responses of SnO/Pt/WO sensors toward NH and H gases were slightly lower than those of Pt/SnO sensor film, and the gas response of SnO/Pt/WO sensor films to HS gas was almost negligible. The calcification of NH and H gases was effectively conducted by machine learning algorithms. These evidences manifested that SnO/Pt/WO sensor films are suitable for the actual NH detection of NH and HS gases.