Enhanced NH₃ and H₂ gas sensing with H₂S gas interference using multilayer SnO₂/Pt/WO₃ nanofilms

The selective detection and classification of NH₃ and H₂S gases with H₂S gas interference based on conventional SnO₂ thin film sensors is still the main problem. In this work, three layers of SnO₂/Pt/WO₃ nanofilms with different WO₃ thicknesses (50, 80, 140, and 260 nm) were fabricated using the sputtering technique. The WO₃ top layer were used as a gas filter to further improve the selectivity of sensors. The effect of WO₃ thickness on the (NH₃, H₂, and H₂S) gas-sensing properties of the sensors was investigated. At the optimal WO₃ thickness of 140 nm, the gas responses of SnO₂/Pt/WO₃ sensors toward NH₃ and H₂ gases were slightly lower than those of Pt/SnO₂ sensor film, and the gas response of SnO₂/Pt/WO₃ sensor films to H₂S gas was almost negligible. The calcification of NH₃ and H₂ gases was effectively conducted by machine learning algorithms. These evidences manifested that SnO₂/Pt/WO₃ sensor films are suitable for the actual NH₃ detection of NH₃ and H₂S gases.