کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
75435 49115 2011 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Assessing the surface sites of the large pore 3-dimensional microporous material H-ITQ-7 using FT-IR spectroscopy and molecular probes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Assessing the surface sites of the large pore 3-dimensional microporous material H-ITQ-7 using FT-IR spectroscopy and molecular probes
چکیده انگلیسی

H-ITQ-7 ((Si + Ge)/Al = 103) has been synthesized and submitted to thorough characterization, in particular with respect to the acidic properties. The H-ITQ-7 material, being one of very few known zeolite or zeotype materials with a three dimensional large pore channel structure, is of particular interest due to its structural similarities with the well studied and industrially relevant H-beta zeolite. By using a variety of molecular probes (H2O, CH3OH, CO, and pyridine) in combination with FT-IR spectroscopy, detailed insights regarding the acidic character of the various surface sites have been obtained. The use of several probes is required, as complementary knowledge is gained. Al containing H-ITQ-7 possesses strong Brønsted acid sites of at least two families that are clearly seen to interact differently with both CH3OH and CO. The spectral features observed upon adsorption of H2O and CH3OH indicate that the Brønsted acid sites of H-ITQ-7 are of strength comparable to those of H-beta. However, the spectra recorded upon adsorption of the more sensitive CO probe suggest that the acid strength of the Brønsted sites of H-ITQ-7 is slightly lower than those of several other acidic zeolites. H-ITQ-7 is an active catalyst in the conversion of methanol to hydrocarbons at 400 °C, a reaction that requires strong Brønsted acidity, and the product shape selectivity observed indicates that the pores of H-ITQ-7 are slightly more restricted than those of H-beta.

By using FTIR in combination with H2O, CH3OH, CO, and pyridine as molecular probes, detailed insights regarding the acidic character of the various surface sites of H-ITQ-7 have been obtained.Figure optionsDownload as PowerPoint slideResearch highlights
► H-ITQ-7 possesses strong Brønsted acid sites of at least two families.
► The Brønsted sites of H-ITQ-7 are slightly less acidic than those of other zeolites.
► H-ITQ-7 is an active catalyst in the conversion of methanol to hydrocarbons.
► The channels of H-ITQ-7 are slightly more restricted than those of H-beta.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microporous and Mesoporous Materials - Volume 141, Issues 1–3, May 2011, Pages 146–156
نویسندگان
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