Scanning Electrochemical Microscopy Studies of Redox Processes at Undoped Nanodiamond Surfaces
Scanning Electrochemical Microscopy Studies of Redox Processes at Undoped Nanodiamond Surfaces
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DOI：
10.1021/jp8038384
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发表时间：
2009-01
影响因子：
3.7
通讯作者：
K. Holt;C. Ziegler;J. Zang;Jing-yu Hu;J. Foord
中科院分区：
文献类型：
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作者：
K. Holt;C. Ziegler;J. Zang;Jing-yu Hu;J. Foord
利用循环伏安法（CV）和扫描电化学显微镜（SECM）以及氧化还原介质Fe（CN）63-、Fe（CN）64-、二茂铁甲醇（FcOH）和Ru（NH3）63+研究了化学气相沉积法生长的未掺杂纳米金刚石（ND）膜的氧化还原行为。CV显示所有氧化还原对的动力学都非常缓慢，但与Fe（CN）64−的氧化相比，Fe（CN）63-的还原速度特别慢。SECM证实了这一趋势，通过将接近曲线与理论拟合得到的实验非均相速率常数为10−3 cm s−1。Fe（CN）64−在过电位下的氧化，|η|发现0.6 V的Fe（CN）63-的还原速度比相同条件下Fe（CN）63-的还原速度快5倍。|η|.假设传导发生通过扩展sp2（石墨和缺陷网站）通过膜的结果进行解释。膜的非金刚石组分将杂质带引入允许有限金属型导电性的带隙中。慢电子T…
The redox behavior of an undoped nanodiamond (ND) film grown by chemical vapor deposition was investigated using cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) and redox mediators Fe(CN)63−, Fe(CN)64−, ferrocenemethanol (FcOH), and Ru(NH3)63+. CV showed extremely sluggish kinetics for all redox couples, but the reduction of Fe(CN)63- was found to be especially slow when compared to the oxidation of Fe(CN)64−. SECM confirmed this trend, with experimental heterogeneous rate constants, obtained by fitting approach curves to theory, being of the magnitude of 10−3 cm s−1. The oxidation of Fe(CN)64− at an overpotential, |η|, of 0.6 V was found to occur 5 times faster than the reduction of Fe(CN)63− at the same |η|. The results are explained by assuming conduction takes place through extended sp2 (graphitic and defect sites) through the film. The nondiamond component of the film introduces impurity bands into the band gap that allows limited metallic type conductivity. The slow electron t...