کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7716782 | 1497473 | 2014 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Integrated Ni/Nb2O5 nanocatalytic agent dose for improving the hydrogenation/dehydrogenation kinetics of reacted ball milled MgH2 powders
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
الکتروشیمی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Integrated Ni/Nb2O5 nanocatalytic agent dose for improving the hydrogenation/dehydrogenation kinetics of reacted ball milled MgH2 powders Integrated Ni/Nb2O5 nanocatalytic agent dose for improving the hydrogenation/dehydrogenation kinetics of reacted ball milled MgH2 powders](/preview/png/7716782.png)
چکیده انگلیسی
Reactive ball milling (RBM) technique was employed to synthesize ultrafine powders of MgH2, using high energy ball mill operated at room temperature under 50 bar of a hydrogen gas atmosphere. The MgH2 powders obtained after 200 h of continuous RBM time composed of β and γ phases. The powders possessed nanocrystalline characteristics with an average grain of about 10 nm in diameter. The time required for complete hydrogen absorption and desorption measured at 250 °C was 500 s and 2500 s, respectively. In order to improve the hydrogenation/dehydrogenation kinetics of as synthesized MgH2 powders, three different types of nanocatalysts (metallic Ni, Nb2O5 and (Ni)x/(Nb2O5)y) were utilized with different weight percentages and independently ball milled with the MgH2 powders for 50 h under 50 bar of a hydrogen gas atmosphere. The results showed that the prepared nanocomposite MgH2/5Ni/5Nb2O5 powders possessed superior hydrogenation/dehydrogenation characteristics, indexed by low values of activation energy for β-phase (68 kJ/mol) and γ-phase (74 kJ/mol). This nanocomposite system showed excellent hydrogenation/dehydrogenization behavior, indexed by the short time required to uptake (41 s) and release (121 s) of 5 wt% H2 at 250 °C. At this temperature the synthesized nanocomposite powders possessed excellent absorption/desorption cyclability of 180 complete cycles. No serious degradation on the hydrogen storage capacity could be detected and the system exhibited nearly constant absorption and desorption values of +5.46 and â5.46 wt% H2, respectively.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Hydrogen Energy - Volume 39, Issue 36, 12 December 2014, Pages 21097-21106
Journal: International Journal of Hydrogen Energy - Volume 39, Issue 36, 12 December 2014, Pages 21097-21106
نویسندگان
M. Sherif El-Eskandarany, Ehab Shaban, Ahmed Al-Shemmiri,