Flake-like WO3 decorated by PdRh nanoalloys: Sensing performance, DFT calculation, and machine learning-enhanced selectivity for triethylamine gas detection

Abstract

Bimetallic noble metal alloys attract extensive attention due to their excellent sensitization effects. Based on this, we synthesize monodisperse palladium (Pd) rhodium (Rh) alloy nanoparticles (NPs) and WO₃ spheres composed of flakes via a one-step hydrothermal method, followed by fabricating PdRh@WO₃ sensing materials with different mass percentages using an impregnation method. Testing revealed that at 240°C, the sensor based on 0.6 wt% PdRh@WO₃ exhibits a high response value of 240 toward 100 ppm triethylamine (TEA), approximately 33 times higher than that for ammonia and 62 times higher than formaldehyde, with response/recovery times of 20 s (s) and 27 s, respectively. The combination of density functional theory (DFT), gas chromatography-mass spectrometry (GC-MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) further confirms that the PdRh alloy promotes TEA adsorption and charge transfer. Two machine learning models, random forest (RF) and support vector machine (SVM), achieve accurate discrimination between TEA and interfering gases, further verifying the sensor's high selectivity. Moreover, the sensor demonstrates excellent applicability through real-time environmental simulations using an STM-32 microcontroller platform. This study provides a new solution for rapid detection and real-time monitoring of TEA in industrial production.