A Phase Separation Route to Synthesize α-Fe2O3 Porous Nanofibers via Electrospinning for Ultrafast Ethanol Sensing

A facile and economic procedure was provided to synthesize alpha-Fe2O3 nanofibers. In this procedure, porous alpha-Fe2O3 nanofibers were obtained by a single-polymer/binary-solvent system, while solid alpha-Fe2O3 nanofibers were prepared by a single-polymer/single-solvent system. The crystal structure and morphology of both samples were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption isotherms. The formation mechanism of porous structure was based on solvent evaporation-induced phase separation by the use of mixed solvents with different volatility. Furthermore, ethanol-sensing performance of the porous alpha-Fe2O3 nanofibers was evaluated and compared with solid alpha-Fe2O3 nanofibers. Results from gas-sensing measurements reveal that porous alpha-Fe2O3 nanofibers exhibit higher sensitivity and slightly longer recovery time than solid alpha-Fe2O3 nanofibers. Over all, the gas sensor based on porous alpha-Fe2O3 nanofibers shows excellent ethanol-sensing capability with high sensitivity and ultrafast response/recovery behaviors, indicating its potential application as a real-time monitoring gas sensor.