Electrode macro-sized

Many electrochemical conversions of solid compounds and materials, including for example the corrosion of metals and alloys or the electrochemical conversions of most battery materials, take place within a liquid electrolyte environment, with the classic approach to investigation comprising macro-sized electrodes. However, in order to obtain a comprehensive understanding ofthe mechanism ofthese solid-state electrochemical reactions, the simple technique of immobilizing small amounts of a solid compound/material on an inert electrode surface provides an easy, yet sometimes exclusive, access to their study. In this chapter is presented a survey of the recent developments of this approach, which is referred to as the voltammetry of immobilized microparticles (VIM). Attention is also focused on progress in the field of theoretical descriptions of solid-state electrochemical reactions. 

The study of these reactions forms part of the main body of electrochemical research conducted during the past 200 years. Naturally, the majority ofthe studies were performed with macro-sized electrodes, mainly because the technical systems were of such size, although an additional reason was that the experimental handling... 

Calculate the transport-limited current for the one-electron oxidation of a 1 mM aqueous solution of ferrocyanide, Fe(CN)g , at a macro-channel electrode of size 4.0 mm X 4.0 mm in a flow cell of cross-section dimensions 6 mm x 0.4 mm at flow rates (Vf) of 10 and 10 cm s . Assume a value of 6x10 cm s for the diffusion coefficient of ferrocyanide. 

First, the distance between each microelectrode in the array and the size of each microelectrode must be considered so that the array may realize the properties of a single microelectrode. That is, if the packing density is low, the diffusion layers will overlap and the array will behave as a macro-sized electrode [4]. In the method used in this work, the distances between the microdisk electrodes were controlled by the mask pattern, and the electrode size was controlled by the sharpness of the etched silicon substrate tips, which depend on etching conditions. A diamond array with... 

Range of electrode sizes Fiexibiiity (macro and microdimensions) Limited to macrodimensions Limited by the size of the tip Limited by the size of the tip... 

An electrochemical Pt deposition from the diamine nitrite solution onto monoctystalline, macro- and mesoporous silicon is presented. Pt grain size versus deposition time was determined from the SEM data. A catalytic reactivity of the Pt coated electrodes was estimated by the calculation of the effective surface area with a voltammetry technique. 

Based on equivalent circuit models of the cell component resistances [66], maximum ceU performance of SC-SOFCs with coplanar electrodes is predicted for very small electrode widths (6-10 pm) and gap sizes (2-12 pm). Performance comparisons of macro-, miUi-, and microcells [71] revealed a 10 times higher power density for the micro SC-SOFC which had smaller inter-electrode gaps and electrode widths. As closely spaced small-scale electrodes lower the ohmic resistance and the inter-digitated electrode pattern maximizes the electrode surface area, miniaturization of SC-SOFCs with coplanar, interdigitated electrodes is expected to yield suitable cell performance for small- and microscale power applications. The fabrication of microcells (Figure 2.3) presents many challenges and requires the manufacturing of coplanar microscale electrode patterns from multicomponent ceramic materials. 

It is relatively easy to extract the kinetic parameters of a one-step irreversible ET reaction from a linear sweep voltammogram obtained at a large, e.g., mm-sized electrode (see Chapter 6 for discussion of the differences between macro- and microelectrode behaviors). The transfer coefficient a can be found from the slope of the linear dependence of the peak current vs. square root of the potential scan rate (i vs. 

A microelectrode is an essential element in an SECM. Precisely, the microelectrode is the probe with which the surface of the sample is scanned. The lateral resolution of the SECM is determined by the size of the scanning probe. Therefore, micro-electrodes of small dimensions are necessary to obtain laterally highly resolved images. Decreasing the size of the electrode from macro- to micro-scale brings additional features to the electrode behavior. The special properties of microelectrodes are very important not only to their application in SECM. The small size of a microelectrode influences two key parameters (i) the mass transport of species and (ii) the current line distribution. 

Ngamchuea K, Eloul S, TschuKk K, Compton RG (2014) Planar diffusion to macro disc electrodes - what electrode size is required for the Cottrell and Randles-Sevdk equations to apply quantitatively J Solid State Electrochem 18 3251-3257... 

In Sections 15.2 through 15.6, the terminologies macropores and micropores are based on that used in porous electrode theory, with the term macropores denoting the electrolyte-filled continuous interparticle space in between carbon particles, serving as transport pathways for ion transport across the electrode, whereas the term micropores is used for all the pore space within the carbon particles (intraparticle porosity see Figure 15.5b). In Section 15.7, the formal lUPAC terminology for porous material characterization is used where macro-, meso-, and micropores are distinguished on the basis of the pore sizes in a porous material. ... 

It is often difficult to compare internal resistance of different sizes of MFCs side by side. For a macro/meso-scale MFC, the internal resistance can be as low as several to 10 s of 2, while most miniaturized MFCs have internal resistance on the order of k 2, because generally a larger size electrode results in a smaller internal resistance. Electrical resistance can be shown as ... 

This chapter concerns arrays of electrodes, or electrochemical cells, that have been applied to bioanalytical assays. These arrays are orderly arrangements of elements, with a minimum of two, that are uniquely and individually addressable. Ensemble electrodes, in which all of the exposed macro-, micro-, or nano-sized sensing elements are connected to a single source of stimulus and measurement of response, are not considered, nor are electrode arrays that are used for electrical stimulation (for example, arrays used for cochlear implant stimulation) without measurement of an analyte-selective response. 

Since the main advantage of NEEs over conventional macro (mm-sized) or even ultramicro- (pm-sized) electrodes is a dramatic lowering of double layer capacitive currents in case of inability to directly characterize the morphology of the electrodes, the lack of this characteristic should be taken into account as a diagnostic parameter to discriminate well-prepared from defective NEEs. 

The significant improvement in electrochemical performances of the HMC as an anode in the LIB, electrode material for the EC and cathode catalyst support for Pt in H2-fueled PEMFC are attributed to unique structural properties of the HMC. In particular, the 3D-interconnected nanostructure with hierarchical porosity, providing not only large specific surface area and high mesopore volume for high specific capacitance and homogeneous dispersion of nano-sized Pt and Pt-based alloy nanoparticles but also highly developed hierarchical macro/mesoporosity for fast mass transport. 

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