Effects of Al doping on SnO2 nanofibers in hydrogen sensor

Pristine SnO2 and Al-doped SnO2 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–SnO2 metastable solid solution is formed at the low concentrations, while the Al2O3–SnO2 heterojunction structures can be obtained at high concentrations. Comparing with the pristine SnO2 nanofibers, Al-doped SnO2 composite nanofibers show improved hydrogen sensing properties, with the Al–SnO2 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 SnO2 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.