Utilize este identificador para referenciar este registo: http://hdl.handle.net/10198/1348
Título: Carbon xerogel supported noble metal catalysts for fine chemical applications
Autor: Machado, Bruno
Gomes, Helder
Serp, Philippe
Kalck, Philippe
Figueiredo, José
Faria, Joaquim
Palavras-chave: Carbon xerogel
Selective hydrogenation
Data: 2010
Editora: Elsevier
Citação: Machado, Bruno; Gomes, Helder; Serp, Philippe; Kalck, Philippe; Figueiredo, José; Faria, Joaquim (2010) - Carbon xerogel supported noble metal catalysts for fine chemical applications. Catalysis Today. ISSN 0920-5861. 149:3-4, p. 358-364
Resumo: Carbon xerogels are mesoporous materials obtained upon pyrolysis of the dried gels resulting from polycondensation of resorcinol and formaldehyde. Treatment with nitric acid under severe conditions introduces high amounts of oxygen containing functional groups onto the surface of thematerial, leading however to the collapse of its porous structure. The resulting material is then used to support 1 wt.% Pt, Ir and Ru monometallic catalysts by wet impregnation using organometallic precursors. The catalysts are characterized by N2 adsorption–desorption isotherms at 77 K, temperature programmed desorption coupled with mass spectrometry, scanning and transmission electron microscopy, and H2 chemisorption. The liquid-phase selective hydrogenation of cinnamaldehyde to cinnamyl alcohol is used in order to assess the catalytic performance of the prepared materials. Pt and Ru catalysts are initially very selective towards the hydrogenation of the olefinic double bond, while Ir is mostly selective towards the carbonyl group. After a thermal post-reduction treatment at 973 K, selectivity towards cinnamyl alcohol is significantly improved regardless of the metal nature. The Pt catalyst exhibits the best behavior, a complete shift in C=C to C=O hydrogenation being detected. The improvement in selectivity is rationalized in terms of both an increase in metal particle size and a modification in the surface chemistry of the catalyst after the post-reduction treatment.
URI: http://hdl.handle.net/10198/1348
ISSN: 0920-5861
Versão do Editor: http://www.sciencedirect.com/science/journal/09205861
Aparece nas colecções:CIMO - Artigos em Revistas Indexados ao WoS/Scopus

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