Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts
Alumina-supported lanthanum(III) oxide catalysts at loadings varying in the range 3–30 wt% La 2 O 3 were prepared by wet impregnation and calcination at 920 K for 2 h. An analogous series of catalysts were phosphated by impregnation with up to 6 wt% PO 4 3– from aqueous solutions of (NH 4 )H 2 PO 4...
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| Format: | Article |
| Language: | English |
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SAGE Publications
2011-12-01
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| Series: | Adsorption Science & Technology |
| Online Access: | https://doi.org/10.1260/0263-6174.29.10.927 |
| _version_ | 1797288055939268608 |
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| author | Gamal A.H. Mekhemer Ali F. Bukhzam Amal S. El-Towaty Mohamed I. Zaki |
| author_facet | Gamal A.H. Mekhemer Ali F. Bukhzam Amal S. El-Towaty Mohamed I. Zaki |
| author_sort | Gamal A.H. Mekhemer |
| collection | DOAJ |
| description | Alumina-supported lanthanum(III) oxide catalysts at loadings varying in the range 3–30 wt% La 2 O 3 were prepared by wet impregnation and calcination at 920 K for 2 h. An analogous series of catalysts were phosphated by impregnation with up to 6 wt% PO 4 3– from aqueous solutions of (NH 4 )H 2 PO 4 and then calcined similarly. The catalysts thus obtained were characterized by X-ray diffractometry, infrared spectroscopy and nitrogen sorptiometry at 77 K. The adsorption data were analyzed by the BET method and the t-method. The results suggested that lanthanum(III) oxide loadings up to 30 wt% exist as high-dispersion two- and three-dimensional structures on the surface of alumina that are not XRD-detectable (particle size < 2 nm). Strong interactions not only at the liquid/solid interface established during impregnation, but also at the solid/solid interface established during drying and/or calcination, are suggested to be important events in the dispersion mechanism. Phosphation led to the improvement of the two-dimensional lanthanum(III) oxide dispersion (probably in monolayers) rather than the three-dimensional one, most likely through direct bonding of the phosphate groups to exposed La 3+ sites. It is inferred that nitrogen adsorption data can provide valuable qualitative information on the dispersion of supported oxide materials. |
| first_indexed | 2024-03-07T18:43:47Z |
| format | Article |
| id | doaj.art-ad168ea0e9f34f8aa816aebd5ff269c2 |
| institution | Directory Open Access Journal |
| issn | 0263-6174 2048-4038 |
| language | English |
| last_indexed | 2024-03-07T18:43:47Z |
| publishDate | 2011-12-01 |
| publisher | SAGE Publications |
| record_format | Article |
| series | Adsorption Science & Technology |
| spelling | doaj.art-ad168ea0e9f34f8aa816aebd5ff269c22024-03-02T03:15:54ZengSAGE PublicationsAdsorption Science & Technology0263-61742048-40382011-12-012910.1260/0263-6174.29.10.927Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina CatalystsGamal A.H. Mekhemer0Ali F. Bukhzam1Amal S. El-Towaty2Mohamed I. Zaki3 Chemistry Department, Faculty of Arts and Science, Garyounis University, Ajdabya, Libya Chemistry Department, Faculty of Science, Garyounis University, Benghazi, P.O. 1308, Libya Chemistry Department, Faculty of Arts and Science, Garyounis University, Ajdabya, Libya Chemistry Department, Faculty of Science, Minia University, El-Minia 61519, EgyptAlumina-supported lanthanum(III) oxide catalysts at loadings varying in the range 3–30 wt% La 2 O 3 were prepared by wet impregnation and calcination at 920 K for 2 h. An analogous series of catalysts were phosphated by impregnation with up to 6 wt% PO 4 3– from aqueous solutions of (NH 4 )H 2 PO 4 and then calcined similarly. The catalysts thus obtained were characterized by X-ray diffractometry, infrared spectroscopy and nitrogen sorptiometry at 77 K. The adsorption data were analyzed by the BET method and the t-method. The results suggested that lanthanum(III) oxide loadings up to 30 wt% exist as high-dispersion two- and three-dimensional structures on the surface of alumina that are not XRD-detectable (particle size < 2 nm). Strong interactions not only at the liquid/solid interface established during impregnation, but also at the solid/solid interface established during drying and/or calcination, are suggested to be important events in the dispersion mechanism. Phosphation led to the improvement of the two-dimensional lanthanum(III) oxide dispersion (probably in monolayers) rather than the three-dimensional one, most likely through direct bonding of the phosphate groups to exposed La 3+ sites. It is inferred that nitrogen adsorption data can provide valuable qualitative information on the dispersion of supported oxide materials.https://doi.org/10.1260/0263-6174.29.10.927 |
| spellingShingle | Gamal A.H. Mekhemer Ali F. Bukhzam Amal S. El-Towaty Mohamed I. Zaki Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts Adsorption Science & Technology |
| title | Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts |
| title_full | Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts |
| title_fullStr | Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts |
| title_full_unstemmed | Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts |
| title_short | Nitrogen Sorptiometric Study of Phosphation and Dispersion of Lanthanum(III) Oxide on Alumina Catalysts |
| title_sort | nitrogen sorptiometric study of phosphation and dispersion of lanthanum iii oxide on alumina catalysts |
| url | https://doi.org/10.1260/0263-6174.29.10.927 |
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