High-Performance Microchanneled Asymmetric Gd0.1Ce0.9O1.95−ο/sub>–La0.6Sr0.4FeO3−ο/sub>-Based Membranes for Oxygen Separation

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• 作者：Shiyang Cheng ; Hua Huang ; Simona Ovtar ; Søren B. Simonsen ; Ming Chen ; Wei Zhang ; Martin Søgaard ; Andreas Kaiser ; Peter Vang Hendriksen ; Chusheng Chen
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 24, 2016
• 年：2016
• 卷：8
• 期：7
• 页码：4548-4560
• 全文大小：819K
• ISSN：1944-8252

文摘

A microchanneled asymmetric dual phase composite membrane of 70 vol % Gd<sub>0.1sub>Ce<sub>0.9sub>O<sub>1.95−δsub>–30 vol % La<sub>0.6sub>Sr<sub>0.4sub>FeO<sub>3−δsub> (CGO-LSF) was fabricated by a “one step” phase-inversion tape casting. The sample consists of a thin dense membrane (100 μm) and a porous substrate including “finger-like” microchannels. The oxygen permeation flux through the membrane with and without catalytic surface layers was investigated under a variety of oxygen partial pressure gradients. At 900 °C, the oxygen permeation flux of the bare membrane was 1.6 (STP) ml cm<sup>–2sup> min<sup>–1sup> for the air/He-case and 10.10 (STP) ml cm<sup>–2sup> min<sup>–1sup> for the air/CO-case. Oxygen flux measurements as well as electrical conductivity relaxation show that the oxygen flux through the bare membrane without catalyst is limited by the oxygen surface exchange. The surface exchange can be enhanced by introduction of catalyst on the membrane surface. An increase of the oxygen flux of ∼1.49 (STP) mL cm<sup>–2sup> min<sup>–1sup> at 900 °C was observed when catalyst is added for the air/He-case. Mass transfer polarization through the finger-like support was confirmed to be negligible, which benefits the overall performance. A stable flux of 7.00 (STP) ml cm<sup>–2sup> min<sup>–1sup> was observed between air/CO/CO<sub>2sub> over 200 h at 850 °C. Partial surface decomposition was observed on the permeate side exposed to CO, in line with predictions from thermodynamic calculations. In a mixture of CO, CO<sub>2sub>, H<sub>2sub>, and H<sub>2sub>O at similar oxygen activity the material will according to the calculation not decompose. The microchanneled asymmetric CGO-LSF membranes show high oxygen permeability and chemical stability under a range of technologically relevant oxygen potential gradients.