Journal of Membrane Science 185 (2001) 237–243
Preparation of an asymmetric perovskite-type
membrane and its oxygen permeability
Wanqin Jin
1
, Shiguang Li, Pei Huang, Nanping Xu
*
, Jun Shi
Membrane Science and Technology Research Center, Nanjing University of Chemical Technology, Nanjing 210009, PR China
Received 19 April 1999; received in revised form 25 May 2000; accepted 6 November 2000
Abstract
A crack-free asymmetric membrane of perovskite-type oxide (La
0.6
Sr
0.4
Co
0.2
Fe
0.8
O
3-δ
) was successfully prepared by
coating a slurry containing La
0.6
Sr
0.4
Co
0.2
Fe
0.8
O
3-δ
powders directly on the surface of a green support of the same com-
position, followed by sintering. It was found that crack-free asymmetric membranes could be obtained by controlling the
powder concentration of the slurry in the range of 15–25 wt.%. After sintering, the crystal phase of the top layer of asymmetric
membranes prepared was the same as that of powders, which were of the cubic perovskite phase. The nitrogen permeability
and SEM photograph of the support showed that the support was porous, and the gas-tight test and SEM demonstrated that
the top layer of asymmetric membrane was dense and crack-free. The asymmetric membrane prepared, whose dense top layer
was 200 m thick, exhibited about three to four times as high an oxygen flux as a 2 mm dense sintered disc. © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Ceramic membrane; Asymmetric membrane; Membrane preparation and structure; Perovskite-type oxide
1. Introduction
Perovskite and other related phases from the
La
1-x
Sr
x
Co
1-y
Fe
y
O
3-δ
family have been found
to exhibit substantial ionic and electronic conduc-
tivity at elevated temperatures [1–8]. This behav-
ior makes them attractive candidate materials for
many important applications such as solid oxide
fuel cell cathode [6], oxygen separation mem-
branes [1–5,7–9] and membrane reactors for syngas
*
Corresponding author. Tel.: +86-25-3316755-3099;
fax: +86-25-3300345.
E-mail addresses: wqjin@public1.ptt.js.cn (W. Jin),
npxu@dns.njuct.edu.cn (N. Xu).
1
Present address: Nanjing University of Traditional Chinese
Medicine, Nanjing 210029, PR China.
production and the partial oxidation of hydrocarbons
[10–17].
The study on the supported perovskite dense
membranes for oxygen permeation was started a
decade ago. Teraoka et al. [18] were the first to
fabricate a thin-film of La
0.6
Sr
0.4
CoO
3-δ
on a
porous sintered La
0.6
Sr
0.4
CoO
3-δ
support (asym-
metric membrane structure) by means of sput-
tering and spray-deposition. They found that, the
spray-deposition technique could obtain an almost
dense layer about 15 m thick, which exhibited about
twice as high a rate of oxygen permeation as the
dense unsupported membrane (same composition)
of 1.5 mm thickness. But, the oxygen flux observed
by them was lower than expected. They attributed it
to the change in chemical composition at membrane
surface. From then, a few researchers [19–22], have
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PII:S0376-7388(00)00650-5