کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6604940 | 1424098 | 2018 | 35 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Electrochemistry of vanadium redox couples on nitrogen-doped carbon
ترجمه فارسی عنوان
الکترودهای زنجیره ای وانادیم بازآفرینی بر کربن نیتروژن
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
چکیده انگلیسی
The redox reaction of vanadium ions (V2+â3+â4+â5+) on well-developed nitrogen-doped ordered mesoporous carbon (NOMC) was extensively investigated in different electrolyte solutions by electrochemical methods. It is found that both the electronic structure modulated by nitrogen doping and the enriched electrochemically active functional groups on NOMC favor the three electrochemical transitions between the adjacent couples, viz. V2+â3+â4+â5+, as compared with Vulcan XC72 carbon black. Salient findings are as follows. First, the transition of V3+â2+ is the same on the two distinctly different carbons, which indicates that this reaction is an outer-sphere charge transfer reaction. The concomitant hydrogen evolution reaction makes NOMC unsuitable to be used as a negative electrode material in flow batteries. Second, the transition of V5+â4+ shows a quasi-reversible behavior, indicating that NOMC can be used as a positive electrode material. Simulation of cyclic voltammogram (CV) reveals that the standard rate constant and the adsorption equilibrium constant are (7.0 ± 0.9)*10â3 cm sâ1 and 0.70 ± 0.09 (both V4+ and V5+), respectively. Third, the transition of V4+â3+ is recognized in the CV curve, which proceeds in a quasi-reversible reaction. The preceding adsorption of the symmetrical ions (V3+) is found to play a key role in determining the kinetics. Finally, for the two latter transitions, the content of dopant nitrogen yields a negligible effect on the electrochemical activity, excluding the possibility of its direct involvement in electrocatalysis. The above findings not only reveal the applicability of the nitrogen-doped carbon to be used as an electrode material in flow batteries, but also offer an in-depth understanding of the reaction mechanism of vanadium redox couples.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 259, 1 January 2018, Pages 687-693
Journal: Electrochimica Acta - Volume 259, 1 January 2018, Pages 687-693
نویسندگان
Ming-yao Liu, Zhi-peng Xiang, Jin-hua Piao, Jian-ying Shi, Zhen-xing Liang,