Characteristic of Proton Conductor Prepared by Spark Plasma Sintering in the Simulated Coke Oven Gas

Abstract

The SrZr_0.9Y_0.1O_3-α of proton conductor was prepared by normal sintering and SPS (spark plasma sintering) methods in order to separate pure hydrogen gas from the simulated coke oven gas (COG) at high temperature. The SrZr_0.9Y_0.1O_3-α obtained by normal sintering at 1853K for 10 h and SPS at 1773K for 3 min were found to be single phase of perovskite structure. The relative densities of SrZr_0.9Y_0.1O_3-α obtained by SPS at 1673 and 1773K were over 95%. Furthermore, the relative density increased with sintering temperature and time of SPS. The proton conductivity of SrZr_0.9Y_0.1O_3-α of SPS increased with sintering temperature, and was higher than one of normal sintering in dry and wet 10% H₂–90% Ar gases atmosphere. On the other hand, the proton conductivity of SrZr_0.9Y_0.1O_3-α of SPS in the dry and wet simulated COG gas atmosphere was equivalent to one in 50% H₂–50% Ar gases atmosphere. Furthermore, the structure of SrZr_0.9Y_0.1O_3-α was chemically stable in the dry and wet simulated COG gas atmosphere. The applied voltage (V_appl) at 1273K in the wet simulated COG gas atmosphere using SrZr_0.9Y_0.1O_3-α was equivalent to one in wet 50% H₂–50% Ar gases atmosphere, but the electrode polarization (V_appl-iR) was higher. Finally, the hydrogen gas was separated from the wet simulated COG gas atmosphere.