USE OF NIO, ANODICALLY DOPED WITH NI(III), AS REFERENCE ELECTRODE FORGAS SENSORS BASED ON PROTON CONDUCTORS

NiO electrodes, prepared by pressing NiO and alpha-zirconium phosphate powders (1:1 or 1:2 in weight) were anodically doped with Ni(III). Th e use of these electrodes as solid references of gas sensors based on solid state protonic conductors has been investigated. A very low drif t of potential (less than or equal to 0.1 mV per day) and an exchange current density of the order of about 2 mu A/cm(2) were found. Because of the good stability of its potential and the relatively high exchan ge current density, this kind of electrode can be suitably used as bot h reference and as counter-reference electrode in potentiometric and a mperometric sensors, respectively.