A new activation process of bimetallic catalysts and application to the n-hexane isomerization

• Published in: Applied catalysis. A, General Vol. 355; no. 1; pp. 20 - 26
• Main Authors: Yoshioka, Carlos M.N., Jordão, Maura H., Zanchet, Daniela, Garetto, Teresita F., Cardoso, Dilson
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 28-02-2009; Elsevier
• Subjects: Bimetallic catalyst; Catalysis; Chemistry; Exact sciences and technology; Fast activation; General and physical chemistry; Ion-exchange; n-Hexane isomerization; Surface physical chemistry; TEM; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; XANES; Zeolites: preparations and properties; Bimetallic catalyst; XANES; n-Hexane isomerization; TEM; Fast activation; Mixed catalyst; Chemisorption; Electronic properties; Catalytic reaction; Bifunctional catalyst; XANES spectrometry; Hydrogen; Isomerization; Activation; Zeolite; Molecular sieve; Particle; Chemical reduction; Heterogeneous catalysis; Transmission electron microscopy; Acids; Hexane; Diameter; X ray absorption
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2008.10.038

Bimetallic catalysts applied to the
n-hexane isomerization reaction containing Ni and Pt were characterized by X-ray absorption near edge spectroscopy (XANES), transmission electron microscopy (TEM), temperature programmed reduction (TPR) and chemisorption. The metal sites were dispersed in a HUSY zeolite with metallic and acids. The activity was performed using the catalyst activated in different temperatures following a new activation process, named “fast activation method” and the behavior showed maximum catalytic activity at 400
°C activation temperature.
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Bimetallic catalysts applied to the
n-hexane isomerization reaction were prepared with a constant molar content of 130
μmol Me/g
cat of Ni and Pt and characterized in its active form by X-ray absorption near edge spectroscopy (XANES), transmission electron microscopy (TEM), temperature programmed reduction and hydrogen chemisorption techniques. The metal was dispersed in a HUSY zeolite matrix in order to provide both types of sites, metallic and acid, to obtain a bifunctional catalyst. The catalytic activity was evaluated using the catalyst activated at different temperatures following a new activation process, named “fast activation method” and the profile pointed out a maximum catalytic activity when the catalyst was activated at 400
°C. XANES results showed that all samples present similar electronic properties in the studied conditions, despite the differences found in the average particle diameter obtained by TEM, suggesting that the catalytic activity is related to the metal/acid balance.