A solid electrolyte steam sensor with an electrochemically supplied hydrogen standard using proton-conducting oxides

A high temperature solid electrolyte steam sensor with an electrochemically supplied hydrogen as a standard was designed and investigated. Two discs of proton-conducting oxide with porous platinum electrodes were stacked and a small hole was made in order to leak the gas at the interface. Constant voltage was applied to one cell in order to pump up hydrogen from water vapor in atmosphere. EMF of the other cell was measured using the pumped hydrogen as a standard gas. On applying a certain voltage, good EMF response against water vapor pressure was observed over a wide range of PH2O at 700°C.