Synthesis and No_x Gas Sensing Properties of In_1.82 ni_0.18o₃ Electrospun Nanofibers

The detection and control of nitrogen oxides (NOX) in exhaust gases emitted by combustion engines has been an important subject in the last decades. Regulations of vehicle emissions focus on the minimization of NOX in automotive exhaust gases, particularly in lean combustion exhaust gases. Fast response times and high sensitivity of NOX sensor in lean combustion environments are necessary to meet those regulations. In this paper a new sensing material (In_1.82Ni_0.18O₃ nanofibers) was synthesized via a simple and effective electrospinning method. The morphology and crystal structure of the as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectra (XPS). Potentiometric-type NOX sensor based on yttria-stabilized zirconia (YSZ) with In_1.82Ni_0.18O₃ nanofibers sensing electrode was prepared and its gas sensing properties were also tested. The results show that large-scale In_1.82Ni_0.18O₃ nanofibers with diameters ranging from 40 to 80 nm and lengths of several tens of micrometers were successfully synthesized by this technique. A loose reticular porous non-woven lap structure was formed by many fibers. The results of sensing tests show that the sensitivity ∆EMF of sensor prepared can reach 85 mV for 500 ppm NO, and the ∆EMF is stable. Moreover, the sensor also exhibited fast response time and good selectivity.