کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5426491 1395890 2007 4 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effects of potassium on the reaction pathways of CH2 fragment over Mo2C/Mo(1 0 0)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Effects of potassium on the reaction pathways of CH2 fragment over Mo2C/Mo(1 0 0)
چکیده انگلیسی

The adsorption and surface reactions of CH2I2 on the K-dosed Mo2C/Mo(1 0 0) have been studied by high resolution electron energy loss spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. Potassium is an effective promoter for the rupture of C-I bond in the adsorbed CH2I2. A partial dissociation of this compound occurred even at 100 K and was completed at 190 K at monolayer K coverage. The dissociation was further promoted by the illumination of coadsorbed layer at 100 K. As revealed by HREELS and XPS measurements the primary products of the dissociation are CH2 and I. Methylene was converted to π-bonded ethylene characterized by Tp = 160 K, and di-σ-ethylene with Tp = 350 K. Other products of the surface reaction are hydrogen and methane. The coupling reaction of CH2 species was clearly facilitated by potassium. The effect of potassium was explained by the extended electron donation to adsorbed alkyl iodide in one hand, and by the direct interaction between potassium and I on the other hand.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 601, Issue 18, 15 September 2007, Pages 3736-3739
نویسندگان
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