High-Precision Multigas Detection Based on Pd–Au Bimetallic Decorated ZnO Gas Sensors and PSO Feature Optimization

To address the demands for efficient detection of combustible gas, such as hydrogen (H2), ethylene (C2H4), and acetylene (C2H2), in complex gas environments relevant to environmental monitoring, industrial safety, and smart homes, we developed zinc oxide (ZnO) gas sensors featuring bimetallic surface decoration with palladium (Pd) and gold (Au). Electron microscopy reveals the surface morphology of the sensing film and Pd/Au codecoration conformation, while X-ray photoelectron spectroscopy supports that codecoration modulates the distribution of surface oxygen species on ZnO. Gas sensing measurements demonstrate that Pd/Au decoration enhances both sensitivity and selectivity toward H2, C2H4, and C2H2. Specifically, a sensor decorated with 0.6 nm Pd and 2.3 nm Au exhibits a 178-fold increase in response to 160 ppm H2. Furthermore, by combining particle swarm optimization algorithm for feature selection with a support vector machine classifier, a recognition accuracy of 96.07% is achieved across seven different pure and mixture gas samples. This study presents a high-accuracy ZnO-based gas sensing platform optimized through both material engineering and machine learning algorithm, providing a reliable solution for real-world applications in industrial safety and environmental monitoring.