Structure–reactivity relationship for reversible action of water vapour on the environment of copper in cu-zsm-5 catalyst for the selective reduction of nox gases : an in-situ x-ray absorption fine structure study
Author
Source
Journal of Saudi Chemical Society
Issue
Vol. 11, Issue 1 (30 Apr. 2007), pp.35-40, 6 p.
Publisher
Publication Date
2007-04-30
Country of Publication
Saudi Arabia
No. of Pages
6
Main Subjects
Topics
Abstract AR
تمت دراسة تأثير بخار الماء على تركيب و حالة النحاس التأكسدية في الحافز Cu-ZSM-5 بوساطة إجراء التفاعل بداخل EXAFS / XANES بعد تحديد ظروف التفاعل المشابه لاختزال NOx.
أوضحت نتائج EXAFS أن هناك اختزال و أكسدة معا للحالة المعدنية لبعض النحاس في الحافز من Cu+ إلى Cu2+ عندما أضيف بخار الماء للحافز عند درجة حرارة ٣٥٠ °م.
الحالة التأكسدية للنحاس Cu2+ تكون عكسية و تختزل إلى Cu+ بالتسخين عند 500 °م و تحت ضغط منخفض.
أيضا تدعم دراسات XANES عمليات الأكسدة و الاختزال العكسية حيث يتأكسد الحافز إلى Cu2+ عند درجة حرارة 350 °م ويعود للاختزال إلى Cu+ تحت ضغط منخفض و عند درجة حرارة 500 °م.
أظهرت دراسات الكروماتوجرافي الغازية عند 500 °م إنطلاق الأكسجين و الهيدروجين مما يدعم العملية العكسية للحافز مع بخار الماء.
Abstract EN
The effect of water vapour on the structure and oxidation state of copper in Cu-ZSM-5 catalyst has been studied by in-situ EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) under reaction conditions similar to those used for NOx reduction.
The EXAFS results show that there is reduction of some copper to metallic state together with the oxidation of Cu + to Cu2 + when the catalyst is treated with water vapour at 350oC.
The Cu2 + is then reversibly reduced back to Cu + when heated in vacuum at 500o C.
XANES studies also support this reversible redox process where the catalyst oxidizes to Cu2 + at 350oC and rereduces to Cu + in vacuum at 500oC.
Gas chromatographic studies at 500oC showed evolution of oxygen and hydrogen supporting the reversibility of catalyst by water vapour.
American Psychological Association (APA)
Siddiqui, M. Rafiq H.. 2007. Structure–reactivity relationship for reversible action of water vapour on the environment of copper in cu-zsm-5 catalyst for the selective reduction of nox gases : an in-situ x-ray absorption fine structure study. Journal of Saudi Chemical Society،Vol. 11, no. 1, pp.35-40.
https://search.emarefa.net/detail/BIM-21390
Modern Language Association (MLA)
Siddiqui, M. Rafiq H.. Structure–reactivity relationship for reversible action of water vapour on the environment of copper in cu-zsm-5 catalyst for the selective reduction of nox gases : an in-situ x-ray absorption fine structure study. Journal of Saudi Chemical Society (Apr. 2007), pp.35-40.
https://search.emarefa.net/detail/BIM-21390
American Medical Association (AMA)
Siddiqui, M. Rafiq H.. Structure–reactivity relationship for reversible action of water vapour on the environment of copper in cu-zsm-5 catalyst for the selective reduction of nox gases : an in-situ x-ray absorption fine structure study. Journal of Saudi Chemical Society. 2007. Vol. 11, no. 1, pp.35-40.
https://search.emarefa.net/detail/BIM-21390
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references : p. 40
Record ID
BIM-21390