Hydrogen permeation characteristics of La₂₇Mo_1.5W_3.5O_55.5

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• 作者：Einar Vø ; llestad ; Camilla K. Vigen ; Anna Magrasó ; Reidar Haugsrud ; ^{reidar.haugsrud@smn.uio.no" class="auth_mail}
• 关键词：Hydrogen flux ; Membrane ; Mixed proton&ndash ; electron conductor ; Lanthanum tungstate ; Ambipolar transport
• 刊名：Journal of Membrane Science
• 出版年：1 July, 2014
• 年：2014
• 卷：461
• 期：Complete
• 页码：81-88
• 全文大小：985 K

文摘

Hydrogen permeation in 30% Mo-substituted lanthanum tungsten oxide membranes, La₂₇Mo_1.5W_3.5O_55.5 (LWMo), has been measured as a function of temperature, hydrogen partial pressure gradient, and water vapor pressure in the sweep gas. Transport of hydrogen by means of ambipolar proton-electron conductivity and - with wet sweep gas - water splitting contributes to the measured hydrogen content in the permeate. At 700 掳C under dry sweep conditions, the H₂ permeability in LWMo was  mL min^鈭? cm^-1, which is significantly higher than that for state-of-the-art SrCeO₃-based membranes. Proton conductivity was identified as rate limiting for ambipolar bulk transport across the membrane. On these bases it is evident that Mo-substitution is a successful doping strategy to increase the n-type conductivity and H₂ permeability compared to nominally unsubstituted lanthanum tungsten oxide. A steady-state model based on the Wagner transport theory with partial conductivities as input parameters predicted H₂ permeabilities in good agreement with the measured data. LWMo is a highly competitive mixed proton-electron conducting oxide for hydrogen transport membrane applications provided that long term stability can be ensured.