Paper
RSC Advances
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evaluated in function of reaction time at 250 C (ESI Fig. S4†)
and presented a quite good conversion stability up to 1 h under
ethanol stream. Although the foam prepared with PLURONIC
2 S. Costacurta, L. Biasetto, E. Pippel, J. Woltersdorf and
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2
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had the highest surface area (105 m
g ), the smaller pore
volume and lower sulfur amount induced the slightly lower
4 L. Martins, D. Cardoso, P. Hammer, T. Garetto,
S. H. Pulcinelli and C. V. Santilli, Appl. Catal., A, 2011, 398,
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conversion of ethanol in the intermediate (between 200 and
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2
75 C) temperature range. In ESI is depicted the ethanol
conversion on a nonsulfated commercial ZrO
2
reference (ESI
5 R. Backov, So Matter, 2006, 2, 452–464.
Fig. S5†). The conversion is below 5% at all temperatures.
Nevertheless, the samples prepared with the cationic and
neutral surfactants OTAB, IGEPAL and PLURONIC allow to
6 M. Faustini, D. Grosso, C. Boissi `e re, R. Backov and
C. Sanchez, J. Sol-Gel Sci. Technol., 2014, 70, 216–226.
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a total conversion of ethanol to ethene (Fig. 7) at 300 C. The
product formation rate of ethene, diethyl ether and acetalde-
hyde during the ethanol conversion reaction as a function of the
temperature for the ceramic foam prepared with different
surfactants were further shown in the Fig. S6 of the ESI.† Other
8 M. A. Alves-Rosa, L. Martins, S. H. Pulcinelli and
C. V. Santilli, So Matter, 2013, 9, 550–558.
9 L. Martins, M. A. A. Rosa, S. H. Pulcinelli and C. V. Santilli,
Microporous Mesoporous Mater., 2010, 132, 268–275.
byproducts were not detected. Consequently, the catalytic 10 M. A. Alves-Rosa, L. Martins, P. Hammer, S. Pulcinelli and
activity clearly depends on the combined effect of a hierarchical C. Santilli, J. Sol-Gel Sci. Technol., 2014, 72, 252–259.
porous structure and a large number of active sites, which can 11 C. C. Beozzo, M. A. Alves-Rosa, S. H. Pulcinelli and
be effectively accessed during the reaction.
C. V. Santilli, Materials, 2013, 6, 1967–1979.
2 F. Carn, A. Colin, M. F. Achard, H. Deleuze, C. Sanchez and
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1
1
4
. Conclusions
The aeration process of zirconia sols is a promising route to
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Catal. A: Chem., 2014, 394, 40–47.
porosity but only modal macropore family. Structural and surface 19 R. A. Comelli, C. R. Vera and J. M. Parera, J. Catal., 1995, 151,
characterizations of the samples showed the high amount of 96–101.
tetragonal phase and both the sulfate and hydroxyls groups on 20 S. Ardizzone, C. L. Bianchi, G. Cappelletti and F. Porta, J.
the surface. This feature evidences the potential of these ceramic Catal., 2004, 227, 470–478.
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and V. Briois, Chem. Mater., 2004, 16, 3995–4004.
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2
Acknowledgements
This work was supported by the CAPES, CNPq and FAPESP
agencies.
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