resumo
The CeO2 nanorods (CeNR) promote the oxidation of ethylbenzene ( PhEt) and cyclohexene with t-BuOOH, at temperatures as low as 55 degrees C. For both substrates the saturated C-H bonds are preferentially activated over the unsaturated ones. The catalyst seems fairly stable towards leaching phenomena. The liquid-phase oxidation catalysis may be associated with the Ce3+/Ce4+ inter-conversion in the one-electron redox processes mediating the formation of tert-butyl-(per)oxy radicals. CeNR is very effective in H2O2 disproportionation. Pre-treatment of CeNR with H2O2 or t-BuOOH prior to the catalytic reaction enhances the reaction rate of PhEt with t-BuOOH in comparison to CeNR. Textural characterization and spectroscopic studies suggest that catalytic activation is associated to defect sites.
palavras-chave
NANOTUBE-ASSISTED SYNTHESIS; CEO2 NANOTUBES; ULTRAVIOLET-ABSORPTION; CONTROLLED CONVERSION; OXYGEN; ETHYLBENZENE; BUTYLHYDROPEROXIDE; NANOPARTICLES; LUMINESCENCE; CYCLOHEXENE
categoria
Chemistry
autores
Macedo, AG; Fernandes, SEM; Valente, AA; Ferreira, RAS; Carlos, LD; Rocha, J
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
João Rocha
Prof. Catedrático
Luís Carlos
Professor Catedrático
Maria Rute de Amorim e Sá Ferreira André
Professor CatedráticoGrupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G4 - Materiais Renováveis e Economia Circular
agradecimentos
We acknowledge the financial support of PTDC, FEDER, FSE and FCT (SFRH/BD/28433/2006). The authors wish to thank Patricia Neves and Salete Balula for their assistance in performing some preliminary catalytic experiments.