A Comparison of Eu-Doped α-Fe2O3 Nanotubes and Nanowires for Acetone Sensing

Pure and Eu-doped (1.0, 3.0, 5.0 wt.%) alpha-Fe2O3 (PFO and EFO) nanotubes and nanowires have been successfully synthesized through the combination of electrospinning and calcination techniques. The structures, morphologies and chemical compositions of the as-obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential scanning calorimetry (TG-DSC) and energy dispersive spectrum (EDS), respectively. To demonstrate the superior gas sensing performance of the doped nanotubes, a contrastive gas sensing study between PFO (EFO) nanotubes and nanowires was performed. It turned out that Eu doping could magnify the impact of morphology on gas sensitivity. Specifically, at the optimum operating temperature of 240 degrees C, the response value of PFO nanotubes to 100 ppm acetone is slightly higher than that of nanowires (3.59/2.20). EFO (3.0 wt.%) nanotubes have a response of 84.05, which is almost 2.7 times as high as that of nanowires (31.54). Moreover, they possess more rapid response/recovery time (11 s and 36 s, respectively) than nanowires (17 s and 40 s, respectively). The lowest detection limit for acetone is 0.1 ppm and its response is 2.15. In addition, both of EFO nanotubes and nanowires sensors have a good linearity (0.1-500 ppm) and favorable selectivity in acetone detection.