Electrospinning Derived NiO/NiFe2O4 Fiber-in-Tube Composite for Fast Triethylamine Detection under Different Humidity

Designing high-performance triethylamine gas sensors with the stable gasresponse and low resistance variation in air under a wide relative humidity range isexpected for human health and environmental surveillance. Here, a novel porous NiO/NiFe2O4fiber-in-tube nanostructure is prepared by the electrospinning process. Thecharacterizations related to microstructure and surface morphology are carried out.Meanwhile, the gas sensing performance of the porousfiber-in-tube NiO/NiFe2O4materials is evaluated and compared systematically. The results indicate that theintroduction of NiO as the second component can not only reduce the baselineresistance of NiFe2O4gas sensors dramatically but also optimize the gas sensingperformance to a significant extent. Especially, the fabricated sensor based on the NiO/NiFe2O4fiber-in-tube with a Ni/Fe molar ratio of 1.5 exhibits the best performance.The gas response while detecting 50 ppm triethylamine at 300 degrees C is about 3.6 timeshigher than that with Ni/Fe molar ratio of 0.5. Moreover, the response values becomemore stable, and the baseline resistance has a lower variation under a wide relativehumidity range, demonstrating the excellent humidity resistance. These phenomena might be ascribed to the distinctive fiber-in-tube nanostructure as well as the heterojunction between NiFe2O4 and NiO.