Theory for staircase voltammetry and linear scan voltammetry on fractal electrodes: Emergence of anomalous Randles-Sevcik behavior
Theory for staircase voltammetry and linear scan voltammetry on fractal electrodes: Emergence of anomalous Randles-Sevcik behavior
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DOI：
10.1016/j.electacta.2013.07.163
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发表时间：
2013-11-30
影响因子：
6.6
通讯作者：
Kant, Rama
中科院分区：
文献类型：
--
作者：
Parveen;Kant, Rama
在可逆电荷转移条件下，建立了随机粗糙电极上阶梯伏安法（SCV）的理论。一个优雅的一般表达式的统计平均电流，涉及单电位阶跃电流瞬态的多电位阶跃（阶梯）电流响应得到使用的Heaviside单位阶跃函数的属性。理论上强调利用功率谱来表征表面的几何无序性。对于有限分形电极，得到了粗糙度平均电流的显式表达式。线性扫描伏安法（LSV）的结果是通过收集每个电位阶跃上特定时间的电流值来获得的。LSV中的特征峰电流和峰电位与分形维数（D-H）、拓扑长度（l（τ））和分形的最小长度尺度（e）有关。粗糙度可诱导显著（类似于15 mV）峰电位偏移。紧急异常Randles-Sevcik行为观察到的中间扫描速率，不仅取决于DH，但也对l和l（τ）。与扩散系数（D）和潜在步长（Δ E）成比例的内部（v（i））和外部（v（o））交叉扫描速率分别是pi Δ艾德/l（τ）（2）和pi Δ艾德/l（2）。经典的Randles Sevcik行为被观察到超过两个交叉扫描速率。2013爱思唯尔有限公司保留所有权利。
A theory for staircase voltammetry (SCV) on randomly rough electrode is developed under reversible charge transfer conditions. An elegant general expression for the statistically averaged current that relates single potential step current transient to the multipotential step (staircase) current response is obtained using properties of Heaviside unit step function. Theory emphasizes the use of power spectrum to characterize the surface geometric disorder. Explicit expression for the roughness averaged current is obtained for finite fractal electrode. The result for linear scan voltammetry (LSV) is obtained by collecting current value at a specific time on each potential step. The characteristic peak current and peak potential in LSV, are dependent on fractal dimension (D-H), topothesy length (l(tau)) and finest length scale of fractality (e). Roughness can induce significant (similar to 15 mV) peak potential shift. Emergent anomalous Randles-Sevcik behavior is observed for intermediate scan rates that depends not only on DH but also on l and l(tau). The inner (v(i)) and outer (v(o)) crossover scan rates proportional to diffusion coefficient (D) and potential step size (Delta E) are pi Delta ED/l(tau)(2) and pi Delta ED/l(2), respectively. Classical Randles Sevcik behavior is observed beyond two crossover scan rates. 2013 Elsevier Ltd. All rights reserved.