Application of anion-conducting lanthanum oxychloride for potentiometric chlorine gas sensors

摘要

The prototype potentiometric chlorine gas sensor was constructed using Na _3Zr _2Si _2PO _(12) (Nasicon) as a solid electrolyte, two-phase (1 - y)LaOCl-yNaCl as a sensing electrode, and 0.85Na _2Ti _3O _7-0.15Na _2Ti _6O _(13) as a reference electrode. Nasicon, 0.85Na _2Ti _3O _7-0.15Na _2Ti _6O _(13) two-phase system and LaOCl powders were prepared by solid-state reaction method. Two-phase materials (1 - y)LaOCl-yNaCl of different compositions were obtained by doping LaOCl with Na _2CO _3. The best preparation conditions were determined based on differential thermal analysis and thermogravimetry (DTA and TG). All the samples were studied by X-ray diffraction (XRD) analysis. Electrical conductivity of (1 - y)LaOCl-yNaCl was measured using electrical impedance spectroscopy (EIS). The source voltage (SV) of the fabricated cell was measured as a function of temperature (400-600 °C), Cl _2 partial pressure in the range 1-9 Pa and time. Constructed sensor shows the most effective performance at 500 °C and in Cl _2 pressure range of 3-9 Pa.