A high-temperature electrochemical sensor based on CaZr0.95Sc0.05O3–δ for humidity analysis in oxidation atmospheres

A way of in situ water vapor partial pressure determination in oxidizing atmospheres and high temperatures is proposed in this work, utilizing a new and simple amperometric-type sensor design made of ZrO 2 - and CaZrO 3 -based electrolytes. These electrolyte membranes allow conduction of oxygen-anions and protons, resulting in full water decomposition on account of the applied potential through an external electrical circuit. At a certain range of applied voltages, a limiting current condition is observed. By plotting the limiting current against temperature and water vapor partial pressure, the functional dependences are obtained, which could be used as the calibration curves for analytical reasons. The proper operation of the developed sensor is confirmed by changing water vapor partial pressures (0.003–0.110 atm) in air and temperatures (675–750 °C). It is found that the sensor’s reading is stable, reproducible, and corresponds to the theoretically predicted values, confirming the test success. The obtained results allow extending the field of possible applications of oxide materials with proton conduction nature. Graphical abstract ᅟ