Polyethylene glycol-directed SnO2nanowires for enhanced gas-sensing properties

Abstract

SnO₂ nanowires with lengths in the tens of micrometres range have been synthesized on a large scale via a facile polyethylene glycol-directed method at ambient temperature followed by a suitable thermal treatment of the precursor nanowires. The morphology of the precursor of the SnO₂ nanowires is tunable by changing the concentration of either SnCl₂ or polyethylene glycol. After calcination, the resulting SnO₂ nanowires retain a similar shape to the precursor, but with hierarchical architecture, which can be considered as one-dimensional nanowires assembled by interconnected SnO₂ nanoparticles with a high surface-to-volume ratio. The SnO₂ nanowires are investigated with XRD, SEM, TEM, and gas sensing tests for detecting CO and H₂. It is found that the present SnO₂ nanowires exhibit a remarkable sensitivity and low detection limit (10 ppm for H₂), as well as good reproducibility and short response/recovery times, which benefit from the unique hierarchical structure with a high surface-to-volume ratio and the 3D network formed by the nanowires.