Hydrogen pumps using high-temperature proton conductors have been examined as a candidate means of hydrogen separation from syngas. Durability to CO 2 is a main concern for the alkali-earth-containing perovskites and was tested for a few typical compositions. Ce-excluded and cerate-zirconate solid solution electrolytes, SrZr 0.9 Y 0.1 O 3-α , and BaCe 0.6 Zr 0.3 Nd 0.1 O 3-α were stable in CO 2 -containing atmospheres, whereas they showed poor overpotential characteristics when platinum electrodes were used. It is demonstrated that the hydrogen pumping properties can be much improved for the case of SrZr 0.9 Y 0.1 O 3-α by the use of palladium anode and SrCe 0.95 Yb 0.05 O 3-α interlayer for the cathode.

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An electrode design with no use of three-phase boundary was investigated using palladium electrode. The hydrogen evolution rate of the palladium electrode cell using SrZr 0.9 Y 0.1 O 3−α electrolyte followed Faraday's law up to 180 mA cm −2 , and the anode and cathode overpotentials were significantly lower than those of a platinum electrode cell, suggesting that the palladium electrode is effective to improve the performance of the hydrogenpumping cell using SrZrO 3 -based electrolyte. The ratedetermining step (RDS) for electrode reaction was also investigated by changing the electrode morphology and hydrogen partial pressure, and it was suggested that the RDS of the anode is a reaction at electrode/electrolyte interface.