PdPt Nanoparticle-Functionalized α-Fe₂O₃ Hollow Nanorods for Triethylamine Sensing

Noble metals (Pd, Pt, and PdPt) nanocrystals with uniform size and good dispersity were synthesized by the oleylamine (OAm) and borane tributylamine complex (BTB) system in a nitrogen atmosphere and employed to functionalize α-Fe2O3 hollow nanorods. The obtained PdPt/α-Fe2O3 composite has high specific surface area (73.5 m2 g–1) and mesoporous structure (∼10.1 nm). The XPS characterization indicated a direct electronic interaction between PdPt and α-Fe2O3 and the strong dissociation effect of PdPt on oxygen. Compared with α-Fe2O3, Pd/α-Fe2O3, and Pt/α-Fe2O3, the PdPt/α-Fe2O3 sensor exhibits higher response (∼98), faster response, and recovery times (7 s/4 s) to 50 ppm of TEA at 190 °C, and the actual detection limit is as low as 100 ppb. The improved sensing performance of the PdPt/α-Fe2O3 sensor was mainly attributed to the high catalytic activity of PdPt to TEA oxidation. In addition, the electronic senstization of Pd and the synergistic effect of PdPt also played an assistant role. The findings reported in this study demonstrate that bimetal decoration is an effective strategy to increase the sensitivity and decrease the working temperature of metal oxide semiconductor (MOS)-based sensors, and PdPt/α-Fe2O3 is a potential sensing material for the TEA sensor.