Y-doped CaZrO3/Co3O4 as Novel Dense Diffusion Barrier Materials for Limiting Current Oxygen Sensor

Herein, we illustrate a feasible strategy to robust the gas sensing of Y-doped CaZrO3 (YxCa1-xZr0.7O3-δ (x=0.05, 0.06, 0.07))/0.1Co3O4 used as the sensing materials. This compound was prepared using solid state reaction technique. The structural, morphological, electrical, and sensing features such as phase identification, microstructure, ionic conductivity, total conductivity and sensitivity of the sensing materials and the fabricated sensors were evaluated by means of X-ray diffraction, scanning electron microscopy, electron-blocking method, electrochemical impedance spectroscopy and cyclic voltammetry. Additionally, the influence of Y-dopant on the properties of YxCa1-xZr0.7O3-δ /Co3O4 was thoroughly studied. XRD results revealed formation of orthorhombic perovskite phase of YxCa1-xZr0.7O3-δ. Moreover, the obtained results from the electrical properties elucidated a high electronic and low ionic conductivities and small polaron conduction of YxCa1-xZr0.7O3-δ/Co3O4. Furthermore, the results confirmed an excellent limiting current plateau for the fabricated oxygen sensor based on YxCa1-xZr0.7O3-δ/Co3O4. Specially, the experimental observation indicates that the substitution of Y-doping at Ca-site and/or Zr-site might be difficult.