Ultra-sensitive and selective acetone gas sensor with fast response at low temperature based on Cu-doped α-Fe₂O₃ porous nanotubes

In the present work, the acetone gas sensing material based on pure α-Fe₂O₃ nanotubes, pure and Cu-doped α-Fe₂O₃ porous nanotubes were fabricated by electrospinning and annealing processes. Different Cu dopant concentrations are introduced to investigate the dopant’s role in sensing performance. The structures and chemical compositions of the as-prepared products were examined using a series of material characterization methods including XRD, EDS, SEM and nitrogen adsorption–desorption analysis. And the acetone sensing results demonstrate that the gas sensitivity of porous nanotubes is better than nanotubes. Moreover, compared with pure samples, the sensor based on 3.0 wt% Cu-doped α-Fe₂O₃ porous nanotubes exhibits higher response (99.43/100 ppm) and excellent selectivity towards acetone at 164 °C. Meanwhile, the detection limit can extend down to ppb level (2.2/100 ppb). Additionally, the sensor also shows fast response and recovery time (5/18 s) and good repeatability to acetone. The enhancement of gas sensitivity is ascribed to not only the effective utility of hollow and porous structures, but also the high catalytic activity of the Cu additive.