Titre:	Effect of cerium loading on structure and morphology of modified Ce-USY zeolites
Auteur(s):	Garcia, Fillipe Augusto da Costa Araújo, Daniel Ribeiro Silva, Júnia Chaves Marinho e Macedo, Julio Lemos de Ghesti, Grace Ferreira Dias, Sílvia Cláudia Loureiro Dias, José Alves Rocha Filho, Geraldo N.
Assunto::	Zeólitas Óxido de cério Troca iônica Espectroscopia de Raman Ressonância magnética nuclear
Date de publication:	oct-2011
Editeur:	Sociedade Brasileira de Química
Référence bibliographique:	GARCIA, Fillipe A. C. et al. Effect of cerium loading on structure and morphology of modified Ce-USY zeolites. Journal of the Brazilian Chemical Society, São Paulo, v. 22, n. 10, p. 1894-1902, out. 2011. DOI: http://dx.doi.org/10.1590/S0103-50532011001000010. Disponível em: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532011001000010&lng=en&nrm=iso. Acesso em: 12 jan. 2021.
Abstract:	This work describes comprehensibly the effect of cerium loading on the structure and morphology of NH4USY zeolite. The Ce-USY (2-25 wt.% of CeO2) was obtained by wet impregnation of CeCl3 followed by calcination at 550ºC for 8 h. At low loadings (2-10%), cerium species are mainly located at ion exchange positions in the framework, whereas at higher loadings (15-25%), small aggregates were formed on the HUSY surface. X-ray diffractograms (XRD) exhibited only the reflections related to HUSY, demonstrating the high dispersion of cerium species, but Fourier transform Raman spectroscopy (FT-Raman) detected CeOx for the materials above 10%. Reaction of CeCl3 with NH4USY produced NH4Cl, which decomposed to form HCl, leading to framework dealumination. The materials showed an increased Lewis/Brønsted ratio with increasing cerium loadings due to the interaction between the excess cerium and the OH groups of USY, and the consequent formation of CeOx species.
metadata.dc.description.unidade:	Instituto de Química (IQ)
Licença::	Journal of the Brazilian Chemical Society - All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License (CC BY NC 4.0). Fonte: https://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532011001000010&lng=en&nrm=iso&tlng=en. Acesso em: 12 jan. 2021.
DOI:	https://dx.doi.org/10.1590/S0103-50532011001000010
Collection(s) :	Artigos publicados em periódicos e afins

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