Electronic sensitization of the response to C₂H₅OH of p-type NiO nanofibers by Fe doping

Abstract

Pure and 0.18-13.2 at.% Fe-doped NiO nanofibers were prepared by electrospinning and their gas sensing characteristics and microstructural evolution were investigated. The responses ((Rg - Ra)/Ra, where Rg is the resistance in gas and Ra is the resistance in air) to 5 ppm C2H5OH, toluene, benzene, p-xylene, HCHO, CO, H2, and NH3 at 350-500 ° C were significantly enhanced by Fe doping of the NiO nanofibers, while the responses of pure NiO nanofibers to all the analyte gases were very low ((Rg - Ra)/Ra = 0.07-0.78). In particular, the response to 100 ppm C2H5OH was enhanced up to 217.86 times by doping of NiO nanofibers with 3.04 at.% Fe. The variation in the gas response was closely dependent upon changes in the base resistance of the sensors in air. The enhanced gas response of Fe-doped NiO nanofibers was explained in relation to electronic sensitization, that is, the increase in the chemoresistive variation due to the decrease in the hole concentration induced by Fe doping.

Ultrasensitive and low detection limit of acetone gas sensor based on W-doped NiO hierarchical nanostructure

“…Moreover, R a increased with increasing the W doping amount from 0.0 at% to 6.0 at%. This phenomenon could be explained by the decrease of the hole concentration due to the doping of W [41]. The responses of four kinds of sensors as the function of the acetone concentration ranging from 10 to 1000 ppm at 250 °C are depicted in Fig.…”

“…Meanwhile, the study about optimizing the sensing properties of the NiO-based gas sensor by doping method has been A c c e p t e d M a n u s c r i p t 4 developing gradually. Yoon et al [41] have been demonstrated that the response to 100 ppm ethanol could be enhanced up to 217.86 times via doping NiO nanofibers with Fe 3+ . Kim et al [25] also have provided an evidence of enhanced gas responses to toluene and xylene by doping NiO spheres with Cr 3+ .…”

“…The results revealed that the sensor based on the 4.0 at% W-doped NiO had a relatively excellent selectivity to acetone. It is well known that the selectivity is closely the different reaction activities of the analyte gases to the sensing material[41]. The reaction activities of the analyte gases can be greatly influenced by the operating temperature.Meanwhile, the doping of W can induce the increase of defect in the NiO and thus change the surface reaction activity of the sensing material.…”

Synthesis of novel RuO2/NaBi(MoO4)2 nanosheets composite and its gas sensing performances towards ethanol

“…The metal oxides such as ZnO, SnO 2 , TiO 2 , WO 3 , and NiO are prepared into 0D (zero dimensional) nanoparticles, 1D nanotubes, nanowires, and nanofibers [21][22][23], 2-D nanosheets [24] and hierarchical nanostructure [25][26][27] to improve their gas-sensing properties. Kim et al have given a detailed review about the nanostructure materials and their sensing properties [19].…”

Low power consumption micro C2H5OH gas sensor based on micro-heater and ink jetting technique

“…Among them, alcohol detection sensor is needed in many fields; industrial, environmental and human monitoring [12][13][14][15][16][17].…”