کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
611097 1454612 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Interaction of Keggin anions of 12-tungstophosphoric acid with CexZr1−xO2CexZr1−xO2 solid solutions
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Interaction of Keggin anions of 12-tungstophosphoric acid with CexZr1−xO2CexZr1−xO2 solid solutions
چکیده انگلیسی

The interaction of 20 wt% 12-tungstophosphoric acid with CexZr1−xO2CexZr1−xO2 solid solutions has been studied by PXRD, FTIR, FT-Raman, H2-TPR, NH3-TPD, diffuse reflectance UV-vis-NIR, and 31P MAS NMR techniques. The study indicates that the Keggin anions are attached to Lewis metal ion centres and anion vacancies on CexZr1−xO2CexZr1−xO2 supports through WO terminal bonds. The Keggin units at the interface are chemically perturbed as indicated by non-intrinsic IR bands observed at 958 cm−1 (WOter bond), and 1052, 1102 cm−1 (PO bond). NH3-TPD shows that the Keggin anions fixed to Lewis sites and/or oxygen ion vacancies decrease the ammonia uptake on CexZr1−xO2CexZr1−xO2 solid solutions. H2-TPR shows modified redox behaviour of CexZr1−xO2CexZr1−xO2 solid solutions due to the simultaneous reduction of ceria, decomposition of Keggin anions and the reduction of WO3. The broadening of 31P MAS NMR and DR-UV-vis-NIR spectra demonstrate the existence of chemical interactions between the Keggin anions and CexZr1−xO2CexZr1−xO2 supports.

The Keggin anions at the interface directly interact with CexZr1−xO2CexZr1−xO2 solid solutions showing non-intrinsic IR bands assigned to perturbed WOterminal and PO bonds.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 324, Issues 1–2, August 2008, Pages 134–141
نویسندگان
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