کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10245116 47713 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The effect of the reduction temperature on the structure of Cu/ZnO/SiO2 catalysts for methanol synthesis
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
The effect of the reduction temperature on the structure of Cu/ZnO/SiO2 catalysts for methanol synthesis
چکیده انگلیسی
The structure of Cu/SiO2 and Cu/ZnO/SiO2 catalysts was studied after reduction at 450-1300 K. The influence of the ZnO promoter on the exposed Cu surface area and metal cluster size was determined by N2O chemisorption and X-ray diffraction. After reduction at 450 K, the metal surface area amounted to 9 m2/gcat for both catalysts. Oxygen uptake during N2O chemisorption increased significantly up to reduction temperatures of 800-900 K. This increase was most prominent for the ZnO-promoted catalyst, although no oxygen uptake was observed for a similarly treated ZnO/SiO2 sample. The behaviour of the promoted catalyst can be explained by formation of Zn0, surface alloying, and segregation of ZnOx species on top of Cu clusters. The high thermostability of the catalysts was confirmed by in situ XRD measurements. The Cu crystallite size in both catalysts was about 4 nm, and did not increase when the reduction temperature was raised to 1100 K for 1 h.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 229, Issue 1, 1 January 2005, Pages 136-143
نویسندگان
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