Publication Type Journal Article
Title Influence of rare earth elements on the acid and metal sites of Pt/HBEA catalyst for short chain n-alkane hydroisomerization
Authors A. M. P. M. Nunes J M Silva Filipa Ribeiro
Groups
Journal APPLIED CATALYSIS A-GENERAL
Year 2013
Month September
Volume 466
Number
Pages 293-299
Abstract The doping effect of rare earth (RE) elements La, Nd and Yb on the acidity and metal function of Pt/HBEA catalysts was investigated, as well as its influence in the hydroisomerization of n-hexane. HBEA zeolite was submitted to ion exchange with increasing amounts of RE using nitrate solutions, followed by Pt introduction. The samples were characterized by powder X-ray diffraction, chemical analysis and low temperature N-2 adsorption. The acidity of the samples was study through pyridine adsorption followed by FTIR spectroscopy and the model reaction of n-heptane cracking. The influence of RE elements on the metal function was studied by magnetic susceptibility measurements, model reaction of toluene hydrogenation and N-2 chemisorption analysis. The characterization methods showed that the presence of very small amounts of RE elements increases the strength and density of the acid sites due to the appearance of new Lewis acid sites that are detected upon RE loading. The electronic properties and metal dispersion of Pt were also improved. In n-hexane hydroisomerization reaction an increased catalytic activity and selectivity into dibranched isomers is detected in the presence of very low contents of La and Nd (less than 0.4 wt.\%). For higher amounts and also in the case of Yb doped samples, where the amounts introduced were higher, a decrease in catalytic activity as well as a higher selectivity in cracking products is noticed as a result of stereochemical limitations inside the zeolite pore structure. (C) 2013 Elsevier B.V. All rights reserved.
DOI http://dx.doi.org/10.1016/j.apcata.2013.06.043
ISBN
Publisher
Book Title
ISSN 0926-860X
EISSN 1873-3875
Conference Name
Bibtex ID ISI:000324656500035
Observations
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