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 SnO 2 by doping Pd have been investigated. SnO 2 nanoparticles and Pd-SnO 2 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 SnO 2 nanoparticles is very uniform (∼15 nm). The SnO 2 sensor exhibited the highest sensitivity to ethanol at 290 °C. After Pd doping, Pd/SnO 2 sensors not only reduced the optimum working temperature but transformed selectivity from ethanol to TEA. In the Pd-SnO 2 system, the 0.5Pd-SnO 2 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-SnO 2 sensors can be attributed to the improved surface activity of SnO 2 by Pd doping and the catalytic activation of O 2 and TEA by Pd.