Significantly improved triethylamine sensing performance and mechanism of tin oxide by doping Pd: Experimental and DFT studies

Reducing the working temperature and increasing sensitivity and selectivity has always been a research hotspot in the field of MOS based gas sensors. In this work, improved triethylamine (TEA) sensing performance and mechanism of SnO2 by doping Pd have been investigated. SnO2 nanoparticles and Pd-SnO2 with different doping amounts of Pd (0%, 0.1%, 0.3%, 0.5%, and 0.7%) were successfully prepared by the hydrothermal method. The size of SnO2 nanoparticles is very uniform (∼15 nm). The SnO2 sensor exhibited the highest sensitivity to ethanol at 290 °C. After Pd doping, Pd/SnO2 sensors not only reduced the optimum working temperature but transformed selectivity from ethanol to TEA. In the Pd-SnO2 system, the 0.5Pd-SnO2 sensor exhibited high sensitivity (61), fast response-recovery properties (16 s/6 s) to 50 ppm TEA, lower detection limits (0.1 ppm), good repeatability, and higher selectivity. Furthermore, based on density functional theory calculations, the improved TEA sensing performance of 0.5Pd-SnO2 sensors can be attributed to the improved surface activity of SnO2 by Pd doping and the catalytic activation of O2 and TEA by Pd.