Study of the Fe/zeolite-L system: Part I: Characterization of iron species and their structural properties

• Published in: Applied surface science Vol. 165; no. 2; pp. 91 - 99
• Main Authors: Marchetti, S.G, Cagnoli, M.V, Alvarez, A.M, Bengoa, J.F, Mercader, R.C, Yeramián, A.A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 22.09.2000; Elsevier Science
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Ion-exchange; Iron supported on zeolites; Mössbauer spectroscopy; Surface physical chemistry; Volumetric oxidation; Zeolite-L; Zeolites: preparations and properties; Zeolite-L; MP; Volumetric oxidation; Iron supported on zeolites; IO; Mössbauer spectroscopy, structural analysis, 61.18.F; Mössbauer spectroscopy; Structure Solid Surfaces, 68.35.B; ZB; Impregnation; Transition metal Ions; Thermogravimetry; Oxidation; Moessbauer spectrometry; Iron Ions; Zeolite; Ion exchange; Iron Nitrates; Molecular sieve; Modified material
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(00)00364-0

Zeolite-L in potassic (ZLK) and acidic (ZLH) forms were used as a support for iron species to obtain two solids, called Fe/ZLK and Fe/ZLH, respectively. “In situ” Mössbauer spectroscopy (MS) between room temperature (RT) and 15 K, volumetric oxidation (VO) and thermogravimetric analyses were used to determine the iron species existent after reduction (Fe 0, Fe 2+ and Fe 3O 4) and to study their structural properties. In both solids, a similar fraction of very small Fe 0 crystals was found inside the zeolite channels. Intermediate species, like exchanged Fe 2+, were also detected in both samples. It was possible to determine that Fe 2+ ions are located at sites D in Fe/ZLK and sites A in Fe/ZLH. Soft reduction conditions, like slow temperature raise (2 K/min), allowed to maintain metallic Fe crystals inside the zeolite-L structure in contrast with other Fe/zeolite systems.