Recovery of hydrogen from gas mixture by an intermediate-temperature type proton conductor

The characteristics of electrochemical hydrogen pump using one-end closed tube type BaZr(0.955)Y(0.03)Co(0.015)O(3-u), which has higher proton conductivity among other zirconate series proton conductor at the intermediate temperature, were demonstrated by a direct current method in the temperature range from 623 to 873 K. Under water vapor electrolysis condition, mixed proton and electron-hole conduction were exhibited and proton transport number was decreased less than 0.37. On the other hand, under hydrogen pumping from a mixture gas contained with hydrogen gas, proton transport number has attained more than 0.85. However, not only proton and electron-hole conductions but also oxide-ion conduction was exhibited even at lower temperature below 700 K. Thus, the growth of electrochemical failure induced by oxide ion migration was observed. From the standpoint of high proton transport number and low oxide-ion conduction, a candidate proton conductor for nuclear fusion engineering applications was proposed to compare with hydrogen pump characteristics among the zirconate series proton conductor. (C) 2010 Elsevier B.V. All rights reserved.