| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 73789 | Microporous and Mesoporous Materials | 2012 | 6 Pages |
Quantitative IR studies were realized in order to determine the concentration of various kinds of Cu sites in zeolites CuZSM-5, CuITQ-2, CuTNU-9, and CuY. These zeolites contained Cu in the form of Cu2+, Cu+ (in the form of exchange cations Cu+ex. and oxo-form Cu+ox) and metallic Cuo (in reduced samples). The experimental conditions in which known amounts of CO (used as probe molecule) reacted with each kind of Cu sites in CuZSM-5 were elaborated and subsequently the extinction coefficients of IR band of CO in Cun+(CO) adducts were established. Following values of the extinction coefficients of monocarbonyl bands were obtained: 0.11 cm2/μmol for Cu2+(CO), 1.30 cm2/μmol for Cu+ex(CO), 0.91 cm2/μmol for Cu+ox(CO), and 0.79 cm2/μmol for Cuo(CO). The procedure elaborated for CuZSM-5 was also applied for other zeolites. Consequently, the concentrations of Cu2+, Cu+ both in exchange positions and oxo-forms, as well as of Cuo were determined in CuZSM-5 treated at various conditions (reduced, oxidized and treated with H2O) as well as in zeolites CuZSM-5, CuITQ-2, CuTNU-9, and CuY.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Procedure of IR quantitative studies of Cu sites in zeolites is proposed. ► Absorption coefficient of the Cun+(CO) monocarbonyl bands were determined. ► Experimental procedure of quantitative IR studies is effective.
