Synchronous synthesis and sensing performance of alpha-Fe2O3/SnO2 nanofiber heterostructures for conductometric C2H5OH detection

A synthesis procedure based on single-capillary electrospinning and hard-template method was provided to synthesize hierarchical alpha-Fe2O3/SnO2 nanofibers. The samples exhibit unique microstructure where alpha-Fe2O3 nanoparticles were evenly decorated on three-dimensional SnO2 fibrous scaffold. During preparation, the alpha-Fe2O3 nanoparticles and SnO(2 )nanofibers were formed synchronously. Within the composite nanomaterials, the Fe/Sn content ratio can be adjusted by changing the diameter of SnO2 nanofibers backbone. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and nitrogen adsorption-desorption analysis were used to characterize the structure of the synthesized products. By loading alpha-Fe2O3 nanoparticles, the grain growth of SnO2 was effectively restrained during heat treatment in air. The optimum Fe/Sn content ratio of alpha-Fe2O3/SnO(2 )heterostructures with the highest sensitivity was obtained through ethanol sensing measurements. Compared to pure alpha-Fe2O3 and SnO2 nanofibers, the binary composite nanofibers exhibits not only enhanced ethanol sensing response, but also higher dependence of response to the change of ethanol concentration. The remarkable improvement of sensing performance can be attributed to the synergetic effect of the component phases. The influences of heterojunctions on the gas sensing properties of alpha-Fe2O3/SnO2 nanofibers were discussed.