Effects of Al doping on SnO 2 nanofibers in hydrogen sensor

Abstract

Pristine SnO 2 and Al-doped SnO 2 composite nanofibers, with several dopants concentrations, have been fabricated via electrospinning technique and subsequent calcination procedure. The morphology, structure, and composition of the as-prepared nanofibers are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX), respectively. XRD analysis indicates Al–SnO 2 metastable solid solution is formed at the low concentrations, while the Al 2O 3–SnO 2 heterojunction structures can be obtained at high concentrations. Comparing with the pristine SnO 2 nanofibers, Al-doped SnO 2 composite nanofibers show improved hydrogen sensing properties, with the Al–SnO 2 metastable solid solution having the best performances, such as higher sensitivity and rapid response (∼3 s) and recovery (less than 2 s). Effects of the changes of SnO 2 crystal, causing by the induction of Al, on the sensing performance have been discussed. We believe this paper can construct a powerful platform to understand and design the practical gas sensor in future.