Catalytic oxidation of toluene on Ce-Co and La-Co mixed oxides synthesized by exotemplating and evaporation methods

• Tipo: Artigo em Revista Científica Internacional
• Data: 2015

Autores

S. A. C. Carabineiro (Autor) FEUP; X. Chen (Autor) FEUP; M. Konsolakis (Autor) Outra; A. C. Psarras (Autor) Outra; P. B. Tavares (Autor) Outra; J. J. M. Órfão (Autor) FEUP; M. F. R. Pereira (Autor) FEUP; J. L. Figueiredo (Autor) FEUP

Revista

Título: Catalysis Today

Vol. 244

Páginas: 161-171

ISSN: 0920-5861

Editora: Elsevier

Indexação

ISI Web of Knowledge - 61 Citações

ISI Web of Science

Scopus - 103 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia química

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia química

Projetos Associados

LA 20 - Projeto Estratégico-LA 20 - 2011-2012

LA 20 - PROJECTO ESTRATÉGICO - LA 20 - 2013-2014

Outras Informações

ID Authenticus: P-00A-5W9

DOI: 10.1016/j.cattod.2014.06.018

Abstract (EN): Ce-Co and La-Co mixed oxides were synthesized by two different methods: exotemplating and evaporation. The obtained catalysts were evaluated for volatile organic compounds (VOCs) abatement, using toluene as model molecule. The materials were characterized by N2 adsorption at -196 °C, X-ray diffraction (XRD), scanning electron microscopy (SEM), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD) in order to reveal the structure-activity relationship. The results obtained showed the superiority of mixed oxides compared to single oxides in toluene oxidation. Ce-Co mixed oxides were more active than La-Co samples. For Ce-Co materials, the exotemplating method produced catalysts which were more active than those prepared by the evaporation procedure. The former showed the best catalytic performances, with full conversion of toluene into CO2 at about 250 °C. Temperatures higher than 320 °C were required with single oxides. Characterization studies revealed strong interactions between Ce (or La) and Co, leading to a fine dispersion of oxide phases in binary systems. As a result, both the surface area and reducibility of the catalysts increase, which can be accounted for the higher performance of the mixed oxides. Furthermore, NH3-TPD studies showed a linear relationship between acidity and VOC oxidation activity. In fact, a high concentration of weak acid sites is required for high toluene oxidation activity. The results can be explained in terms of a Mars-van Krevelen type of mechanism, involving the adsorption of toluene and its subsequent oxidation by lattice and/or surface oxygen.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 11