Chemical state of a supported iron–cobalt catalyst during co disproportionation: II. Experimental study

• Published in: The Journal of physics and chemistry of solids Vol. 62; no. 6; pp. 1023 - 1037
• Main Authors: Pinheiro, J.P., Gadelle, P., Jeandey, C., Oddou, J.L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2001; Elsevier
• Subjects: A. Alloys; B. Chemical synthesis; B. Vapor deposition; C. Mössbauer spectroscopy; C. X-ray diffraction; Catalysis; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; B. Chemical synthesis; B. Vapor deposition; C. Mössbauer spectroscopy; A. Alloys; C. X-ray diffraction; Binary compound; Disproportionation; Deactivation; Carbon dioxide; Iron Carbides; Aluminosilicates; Moessbauer spectrometry; Experimental study; X ray diffraction; Chemical vapor deposition; Supported catalyst; Iron Alloys; Heterogeneous catalysis; Transmission electron microscopy; Transition metal Alloys; Cobalt Alloys; Carbon monoxide; Cementite; Binary alloy
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/S0022-3697(00)00270-5

X-ray diffraction and Mössbauer spectroscopy have been used to investigate the chemical state of a supported iron–cobalt catalyst during the disproportionation of carbon monoxide at 800 K. The results of this study have demonstrated a strong implication of cementite Fe 3C (may be in association with a cobalt carbide) in the alloy deactivation process. The deactivation due to the carburization is apparently reversible. The catalyst was, indeed, shown to partially recover its activity when submitted to conditions under which the carbide formation was not thermodynamically possible. The results of this study seem to indicate, however, that the alloy deactivation is not the consequence of a single phenomenon but results from the conjunction of two distinct processes. Additional deactivation due to the formation of a carbon layer at the particles surface appears as the most plausible hypothesis to explain this result.