A Computational and Experimental Study of the Cyclic Voltammetry Response of Partially Blocked Electrodes. Part II:  Randomly Distributed and Overlapping Blocking Systems

Abstract

The cyclic voltammetric response of partially blocked electrodes is modeled using finite difference simulations, and a method is presented for the determination of currents at electrode surfaces that have an unstructured blocking pattern. The method is first applied to predict the current at purposely fabricated gold film electrodes in which monodispersed blocking disks are randomly sprinkled over the gold surface. The theoretical models are subsequently applied to the case of a basal plane pyrolytic graphite electrode modified with microdroplets of an electrochemically inactive oil. The theoretically predicted results are in good agreement with those observed experimentally.

Voltammetry at porous electrodes: A theoretical study

“…The electrochemical behavior of flat micro-(and nano-) electrode arrays can be divided into four distinct cases, [16][17][18][19][20][21][22] as summarised in Fig. 2.…”

“…The basis for this is provided by extensive previous simulations which show that only a tiny amount of active surface is required to achieve diffusion control to the entire geometric disc surface. [16][17][18][19][20][21][22] Since…”

Diffusion regimes at nanoelectrode ensembles in different ionic liquids

“…Under these conditions partial overlap of diffusion layers occurs. Theoretical models have been developed for ordered [22,[25][26][27] and random [28] arrays of electrodes.…”

Voltammetric Sizing of Inert Particles

“…[1][2] Such systems are interesting to study because the surface blocking of the electrode modifies the absolute and relative rates of diffusive and kinetic flux to the electrode surface. In addition, the use of microelectrode arrays and the intentional "blocking" of electrodes is becoming increasingly popular, so a good quantitative description of partially blocked electrodes (PBEs) is potentially very useful to a large number of research workers in a variety of applications; for example, over the past two years we have applied our model for PBEs to a number of problems ranging from the measurement of liquid-liquid reaction kinetics to the investigation of electrochemically heterogeneous surfaces.…”

“…[2][3][4][5]7] In previous work we were able to determine the average size of microdroplets on basal plane pyrolytic graphite (bppg) electrodes by comparing experimental peak currents with simulations. [2][3][4][5]7] Similarly, in another study we determined the global coverage of gold particles on edge-plane pyrolytic graphite (eppg) using peak-to-peak separations. [5] We recently developed a method that enables us to simulate the complete cyclic voltammogram for a randomly distributed PBE.…”