Abstract
With the requirement of the regulations which on the NOX emission limits in vehicle emissions is more and more strict. The development of high sensitivity, good repeatability, short response time of NOX sensor, especially for low concentration NOX in engine exhaust is very important. In this paper a new sensing material (NiO nanofiber mixed with ZrO2 nanorods) was synthesized via two simple with effective electrospinning and solvothermal method. The morphology and crystal structure of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The planar NOX sensor based on yttria-stabilized zirconia (YSZ), mixed with NiO-YSZ sensing electrode was prepared by the Multilayered High Temperature Cofired Ceramics (HTCC) technology, and its gas sensitive properties were tested under different NOX concentrations. The results show that ZrO2 product prepared by solvothermal consists of nanorods of about 60 nm in width and 180 nm in length, NiO product prepared by electrospinning consists of nanofiber wtih diameters of about 800 nm; A loose porous structure of sensing electrode was formed by the above two materials. The results of sensing tests show that the sensitivity of sensor prepared can reach 71.5 mV for 400 ppm NO2, and the ΔEmf is very stable. Moreover, the sensor also exhibited fast response and good repeatability for low concentration NOX gas.
KEYWORDS -NOX, NiO nanofiber, ZrO2 nanorod, planner sensor, HTCC