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

4 Results and discussion
nanonic YSZ
γ-Al2O3
α-Al2O3
Figure 63 SEM photograph of a coated nanonic YSZ sol α-and γ-Al2O3 substrate and calcined at 450ºC.
Figure 64 presents the TEM study of the supported 8YSZ layer that included acetyl
acetone, caproic acid and F127. The substrate was prepared from α-Al2O3 and is highly
crystalline. The γ-Al2O3 intermediate layer has a thickness of 6 µm (Figure 64-A). The
YSZ functional layer presents a nanocrystalline phase and has a thickness of only 20-30
nm (Figure 64-B). Nanostructuring due to the addition of F127 could not be observed in
this analysis. Clearly thin cubic YSZ layers can be prepared using the ketone approach.
The cubic phase was identified by Raman spectroscopy (Figure 65). The band at 1155
cm -1 can be assigned to the inorganic bonding of ZrO2 with the Al2O3 supporting layer.
A B
6µm γ-Al2O3
Figure 64 TEM analysis of a membrane: electron diffraction pattern of the (A) α-Al2O3 and (B) γ-Al2O3,
and TEM images of (C) a 6 µm γ-Al2O3 intermediate layer and (D) detail of the top 8YSZ layer that
contained F127, acetyl acetone and caproic acid in the sol (20-30 nm in thickness) on the intermediate
layer.
97
γ-Al2O3
8YSZ+F