Inorganic Microporous Membranes for Gas Separation in Fossil Fuel ...

4 Results and discussion
4.3.3 Sol-Gel derived membrane characterisation
Supported 8YSZ layers were prepared from the ketone sols and characterised with
scanning electron microscopy (SEM), transmission electron microscopy (TEM) and
single gas permeance measurement. Similar analyses are performed on TiO2, ZrO2 and
binary oxide layers that were prepared by amine sols. Additional, X-ray photoelectron
spectroscopy (XPS), Raman spectroscopy and Secondary Ion Mass Spectroscopy (SIMS)
measurements are prepared on the latter.
4.3.3.1 Ketone approach - 8YSZ layers
8YSZ was prepared on glass substrates and on graded porous alumina supports (γ-Al2O3).
Figure 62-B shows a coating applied by simple drying of a film composed of 8YSZ sol
using acetyl acetone, caproic acid and block copolymer F127 (YSZ/F127 ~ 1/4 wt/wt). In
this case, the substrate was a microscope glass slip and the calcination temperature was
500ºC for 2 hours. The obtained film has a thickness of about 200 nm, and a fine porosity
can be observed, although the primary particles cannot be recognized due to the
resolution of SEM technique.
A B
YSZ
Glass Substrate
Figure 62 Cross section SEM image of a coated YSZ sol blended with a block copolymer on a glass slip and
calcined at 500ºC.
Two kinds of 8YSZ layers have been prepared on graded porous γ-Al2O3 membranes
being i) 8YSZ sol using acetyl acetone in combination with nanonic acid and ii) 8YSZ
sol using acetyl acetone, caproic acid and F127. A ~50 nm thin 8YSZ layer is obtained on
a γ-Al2O3 membrane after calcining at 450ºC an 8YSZ sol that included nanonic acid.
The surface and cross section of the membrane indicate a homogeneous layer (Figure 63).
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