Journal of Membrane Science, Vol.512, 104-110, 2016
Electrical conduction and hydrogen permeation investigation on iron-doped barium zirconate membrane
Mixed conducting 10% Fe-doped BaZrO3 (BZE10) membrane was investigated for electrical conduction and hydrogen permeation properties in the temperature range of 600-900 degrees C. A hydrogen permeation flux (JH(2)) as high as 0.75 mL/(min cm(2)) was achieved at 900 degrees C using a 1.15 mm thick BZE10 membrane when 20% H-2/inert and Ar were flowed in the feed and sweep, respectively. J(H2) increases monotonically with the reciprocal of the membrane thickness, indicating bulk diffusion is the rate-limiting step in the examined thickness range (0.97-1.40 mm). At constant temperature, J(H2) increases with the feed side hydrogen partial pressure. In the range of 600-700 degrees C, hydrogen permeation is limited by the electronic transport with high activation energy 72-94 kJ/mol. While in the higher temperature range of 700900 degrees C, hydrogen permeation is limited by the mixed protonic-electronic transport with low activation energy 18-23 kJ/mol. The addition of moisture did not influence J(H2) when the steam level was below 0.1 atm. While when the steam level reached 0.3 atm, hydrogen permeation process was promoted by the formation of extra protons. BZE10 membrane is found to be mechanically and chemically stable over dry and humidified hydrogen containing gas environments. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Protonic conducting membrane;Electrical conduction;Electroceramics;Hydrogen permeation;Iron-doped barium zirconate