H/D Isotope Effect on Electrochemical Pumps of Hydrogen and Water Vapor Using a Proton‐Conductive Solid Electrolyte

From the standpoint of an H/D isotope effect, the electrochemical pumping of hydrogen or water vapor has been studied using a high temperature proton conductor as a solid electrolyte. When a potential was applied to the cell at 1173 K, the pumping rate of deuterium was remarkably smaller than that of hydrogen. During hydrogen pumping, the total current was depressed by replacing H + and D + . In addition, an increase in cathodic overpotential was observed by the current‐in‐terruption method. Similar behavior was recognized in the pumping of water vapor, except that the transport number of the conducting ion decreased with replacement of D + by H + .