Porous double-channel α-Fe2O3/SnO2 heterostructures with multiple electronic transmission routes for the enhanced N,N-dimethylformamide gas-sensing performance

Porous double-channel α-Fe2O3/SnO2 heterostructures with tunable surface/interface transport mechanism have been originally fabricated by the electrospinning and subsequent calcination process. With the increase of Sn content from 0 to 5 mol%, the morphology of α-Fe2O3-based materials changed from porous fibers to ribbons with both sides curled inward. Double-channel structure can provide more active sites and enhanced adsorption capacity with the large specific surface areas of 233.2 m2/g. The optimal α-Fe2O3/SnO2 composites exhibit the highest response value (32.38) and fastest response/recovery times (33/58 s) than those of other samples to 100 ppm N,N-dimethylformamide (DMF) at 360 °C. Meanwhile, good cycling and long-term stability and high gas selectivity of the composites are conductive to the feasible detection to DMF under high temperature (≥360 °C) condition. The enhanced gas-sensitive properties of α-Fe2O3/SnO2 composites at high temperature are closely related to phase composition, unique morphology, efficient n-n heterojunction and accelerated surface/interface charge transfer process. Significantly, the porous double-channel α-Fe2O3/SnO2 composite is expected to be a potential candidate for DMF vapor detection in the dye or pesticide industry to prevent DMF explosion under high temperature conditions in the future. [Display omitted] •Porous double-channel α-Fe2O3/SnO2 heterostructures is gained by electrospinning.•The special structure can provide more active sites and enhanced adsorption capacity.•Superior gas-sensing properties to DMF are obtained at high temperature (≥360 °C).•Fe/Sn-0.03 shows the highest response (32.38) and low detection limit (1 ppm) to DMF.•Sensing behavior depends on surface/interface multiple electronic transport routes.