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The role of surface Zn 2+ ions in the transesterification of vegetable oils over ZnO supported on Al 2 O 3 and Fe 2 O 3
Samples of ZnO–Al 2 O 3 and ZnO–Fe 2 O 3 with different loadings of ZnO (5–20 wt%) were prepared by impregnation of the supports (γ-Al 2 O 3 and α-Fe 2 O 3 ) with ZnNO 3 and calcination at 873 K. XRD studies of the calcined samples revealed that the ZnO had reacted with the support to form the corre...
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| Published in: | Catalysis science & technology 2014, Vol.4 (3), p.851-860 |
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| Main Authors: | , , , , |
| Format: | Article |
| Language: | English |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | Samples of ZnO–Al
2
O
3
and ZnO–Fe
2
O
3
with different loadings of ZnO (5–20 wt%) were prepared by impregnation of the supports (γ-Al
2
O
3
and α-Fe
2
O
3
) with ZnNO
3
and calcination at 873 K. XRD studies of the calcined samples revealed that the ZnO had reacted with the support to form the corresponding spinels, ZnAl
2
O
4
and ZnFe
2
O
4
. The catalytic activity of the supported spinel samples, and samples of stoichiometric ZnAl
2
O
4
and ZnFe
2
O
4
prepared by co-precipitation were examined for the transesterification of sunflower oil, waste cooking oil and Jatropha oil. Linear relationships between the spinel content, estimated by XRD, and surface Zn concentration estimated by XPS and transesterification activity of the samples were obtained. XVB (X-ray valence band) studies provided evidence to suggest that the Zn 3d electrons may have played a major part in the electronic excitation of the spinels (ZnAl
2
O
4
and ZnFe
2
O
4
) and, therefore, their catalytic activity. |
|---|---|
| ISSN: | 2044-4753 2044-4761 |
| DOI: | 10.1039/C3CY00857F |