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

• Type: Article in International Scientific Journal
• Date: 2015

Authors

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

Journal

Title: Catalysis Today

Vol. 244

Pages: 161-171

ISSN: 0920-5861

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 61 Citations

ISI Web of Science

Scopus - 103 Citations

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Technological sciences > Engineering > Chemical engineering

Associated Projects

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

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

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11