High surface area nano-sized catalysts with the general formula La 0.9M0.1CoO3 (M=Ce, Pr, Tb) were synthesised by a novel flame-spray-pyrolysis method. All the prepared samples possessed the LaCoO3 perovskite-like structure and consisted of 30-60 nm particles, but existing as large (80-200 nm) agglomerates. Their surface area ranged from 45 to 60 m2/g. All the catalysts showed a very high activity for methane flameless combustion, attaining 100% conversion at temperatures Tf, between 495 and 515 °C, depending on the nature of the M doping ion. The results of life-tests did not show any decreasing of catalytic activity after 50 h under the reaction conditions at Tf. The thermal stability under high temperature application was investigated by overheating the catalysts twice at 800 °C for 1 hr in a flowing reacting gas mixture, fast deactivation cycles, and then measuring methane conversion at Tf. All the catalysts showed a significant decrease of activity, depending on the chemical composition. Taking account of the results of SEM analysis, this was attributed to sintering, connected with the Gibbs instability of nano-sized materials.

Catalytic activity for methane flameless combustion and thermal stability of nano-sized lanthanum cobaltites doped with Ce, Pr and Tb / A. Y. Kryukov, A. V. Vishniakov, C. Oliva, L. Forni. - In: DIFFUSION AND DEFECT DATA, SOLID STATE DATA. PART B, SOLID STATE PHENOMENA. - ISSN 1012-0394. - 128(2007), pp. 255-260.

Catalytic activity for methane flameless combustion and thermal stability of nano-sized lanthanum cobaltites doped with Ce, Pr and Tb

C. Oliva;L. Forni
2007

Abstract

High surface area nano-sized catalysts with the general formula La 0.9M0.1CoO3 (M=Ce, Pr, Tb) were synthesised by a novel flame-spray-pyrolysis method. All the prepared samples possessed the LaCoO3 perovskite-like structure and consisted of 30-60 nm particles, but existing as large (80-200 nm) agglomerates. Their surface area ranged from 45 to 60 m2/g. All the catalysts showed a very high activity for methane flameless combustion, attaining 100% conversion at temperatures Tf, between 495 and 515 °C, depending on the nature of the M doping ion. The results of life-tests did not show any decreasing of catalytic activity after 50 h under the reaction conditions at Tf. The thermal stability under high temperature application was investigated by overheating the catalysts twice at 800 °C for 1 hr in a flowing reacting gas mixture, fast deactivation cycles, and then measuring methane conversion at Tf. All the catalysts showed a significant decrease of activity, depending on the chemical composition. Taking account of the results of SEM analysis, this was attributed to sintering, connected with the Gibbs instability of nano-sized materials.
Catalytic methane combustion; Flame-spray pyrolysis; Perovskite
Settore CHIM/02 - Chimica Fisica
DIFFUSION AND DEFECT DATA, SOLID STATE DATA. PART B, SOLID STATE PHENOMENA
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/35627
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? ND
social impact