Electrochemical cell representation

This is also the reason why the reversible potential difference of a cell is mentioned with the system composition. Formerly, the reversible potential difference was named the electromotive force of the cell. (For the meaning of the word reversible, see immediately below). For example, the following galvanic cell (see Chap. 13 for the electrochemical cell representations)... 

Shorthand Notation for Electrochemical Cells Although Figure 11.5 provides a useful picture of an electrochemical cell, it does not provide a convenient representation. A more useful representation is a shorthand, or schematic, notation that uses symbols to indicate the different phases present in the electrochemical cell, as well as the composition of each phase. A vertical slash ( ) indicates a phase boundary where a potential develops, and a comma (,) separates species in the same phase, or two phases where no potential develops. Shorthand cell notations begin with the anode and continue to the cathode. The electrochemical cell in Figure 11.5, for example, is described in shorthand notation as... 

Figure 15.2 Schematic representation of different electrochemical cell types used in studies of electrocatalytic reactions (a) proton exchange membrane single cell, comprising a membrane electrode assembly (b) electrochemical cell with a gas diffusion electrode (c) electrochemical cell with a thin-layer working electrode (d) electrochemical cell with a model nonporous electrode. CE, counter-electrode RE, reference electrode WE, working electrode.

Figure 17.7 Electrocatalysis of O2 reduction by Pycnoporus cinnabarinus laccase on a 2-aminoanthracene-modified pyrolytic graphite edge (PGE) electrode and an unmodified PGE electrode at 25 °C in sodium citrate buffer (200 mM, pH 4). Red curves were recorded immediately after spotting laccase solution onto the electrode, while black curves were recorded after exchanging the electrochemical cell solution for enzyme-fiiee buffer solution. Insets show the long-term percentage change in limiting current (at 0.44 V vs. SHE) for electrocatalytic O2 reduction by laccase on an unmodified PGE electrode ( ) or a 2-aminoanthracene modified electrode ( ) after storage at 4 °C, and a cartoon representation of the probable route for electron transfer through the anthracene (shown in blue) to the blue Cu center of laccase. Reproduced by permission of The Royal Society of Chemistry fi om Blanford et al., 2007. (See color insert.)...

Figure 2.15 Schematic representation of the equipment necessary to perform linear sweep voltammetry LSV) or cyclic voltammetry CV). WFG waveform generator, P potentiostat, CR chart recorder, EC electrochemical cell, WE working electrode, CE counter electrode, RE...

Figure 2.25 Schematic representation of the STM head and electrochemical assembly. (I) Inchworm motor, (2) Inch worm, (3) Faraday cage around tube scanner, (4) Teflon electrochemical cell, (5) working electrode (i.e. sample), (6) stainless steel plates, (7) halved rubber O rings, (8) elasticated ropes attatched to baseplate. The counter and reference electrodes and the various electrical connections arc not shown for clarity. From Christensen (1992).

Figure 2,33 Schematic representation of an AFM electrochemical cell and its mode of operation. (I) photodiode, (2) electrolyte solution inlet/outlet, (3) spring clip, (4) cantilever holder, (5) glass cell body, (6) O ring, (7) sample, (8) r, v, z translator, (9) mirror and (10) tip. After Manne et at.

Figure 2.39 (a) Schematic representation of the experimental arrangement for attenuated total reflection of infrared radiation in an electrochemical cell, (b) Schematic representation of the ATR cell design commonly employed in in situ 1R ATR experiments. SS = stainless steel cell body, usually coated with teflon P — Ge or Si prism WE = working electrode, evaporated or sputtered onto prism CE = platinum counter electrode RE = reference electrode T = teflon or viton O ring seals E = electrolyte. 

A schematic representation of the lower half of an EQCM cell is shown in Figure 2.109. The crystal is clipped or glued to the bottom of the electrochemical cell. Within the cell are the reference and counter electrodes, and a purging device to allow N2-saturation of the electrolyte. 

Figure 2.115 shows a schematic representation of the DEMS apparatus. In essence, the electrochemical cell is separated from a mass spectrometer by a porous, non-wetting PTFE membrane of very small pore size. The working electrode is then deposited as a porous metal layer on the thin... 

FIGURE 14.2 A representation of an electrochemical cell as described in the text. One electrode is the anode, the other the cathode, and electrons generated by the oxidation process at the anode flow through the external circuit to the cathode, where reduction takes place. This flow of electrons constitutes electrical current in the external circuit. 

Ionic mobility refers to the velocity of an ion moving toward an oppositely charged electrode when a 1-volt potential is applied across a 1-centimeter electrochemical cell, strongly hydrated molecular cluster, such as [H-(OH2)4], is probably a more realistic representation (M. Eigen (1964) Angew. Chem. (Int. Eng. Edn.) 3, 1). 

Figure 4.2 — (A) Schematic diagram of an ammonia-N-sensitive probe based on an Ir-MOS capacitor. (Reproduced from [20] with permission of the American Chemical Society). (B) Pneumato-amperometric flow-through cell (a) upper Plexiglas part (b) metallized Gore-Tec membrane (c) auxiliary Gore-Tec membrane (d) polyethylene spacer (e) bottom Plexiglas part (/) carrier stream inlet (g) carrier stream outlet. (C) Schematic representation of the pneumato-amperometric process. The volatile species Y in the carrier stream diffuses through the membrane pores to the porous electrode surface in the electrochemical cell and is oxidized or reduced. (Reproduced from [21] with permission of the American Chemical Society).

Fig. 22. Schematic representation of the electrochemical cell connected to a perturbation circuit and a detection circuit for second-order responses. In this case, it is supposed that the perturbation signal has a high frequency and the response signal a low frequency.

Figure 5.1 Schematic representation of an electrochemical cell (a) three electrodes (b) equivalent circuit for three-electrode cell (c) equivalent circuit for the working-electrode interphase (d) a solution impedance in series with two parallel surface impedances.

Figure 18.13 Vacuum electrochemical cell with an integrated drying tube (o) and water-cooled jackets (fl, fZ) from (A) a front view and (B) a top view. Schematic representation of the drying operation is shown in A, B and C. The cell is filled with aluminum oxide and electrolyte solution in A. The solution is transferred into the cell by a 90° rotation in B. After back-rotation, the solution flows into the electrode compartment, passing through the cooled alumina drying tube in C. [From Ref. 2, with permission.]...

One of the most broadly applied equivalent circuits is shown in Figure 4. It consists of a parallel RpC network in with a resistor R. This particular network is a simple representation of an electrochemical cell. R represents the... 

Fig. 1 Schematic representation of e2q)erimental arrangement for tribocorrosion experiments with alumina sphere, load cells and electrochemical cells...

Figure 13. Representation of the potential variations in the electrochemical cell and associated electronic schemes (a-d). ( = cat + Ri + an see text). W, working electrode Ref, reference electrode A, auxiliary electrode, (e) Schematic description of the electrochemical cell with a potentiostat.

Figure 1. Schematic representation of the electrochemical cell. First insert concentration profile of the reactant in the stagnant layer in the vicinity of the electrode. Second insert mass transfer black box at the boundary between the stagnant layer and the bulk solution (x = (5).

Figure 6.1 Schematic representation of the ESI source as electrochemical cell.

Figure 21.1 A schematic representation of the propagation of time-domain errors through an electrochemical cell and impedance instrumentation to the frequency domain.

Figure 21.2 A schematic representation of an electrochemical cell under potentiostatic regulation, with sources of potential noise indicated as shaded circles and sources of current noise indicated as shaded double circles (see Gabrielli et al. ).

It is useful to establish a more generalized representation for the electrochemical cell reaction as follows ... 

In the above description of what happens in a cell, an overall reaction has been found by combination of the reactions occurring at the two electrodes. This overall cell reaction is a formal representation in the sense that it does not actually take place in the cell. The only chemical reactions which actually occur are those at the electrodes, but their net effect corresponds in quantitative terms to what would be expected if the overall chemical reaction did actually occur. The observed potential difference or emf is related to the AG for the overall cell reaction. It is this property of electrochemical cells which makes them so usefirl as they allow determination of thermodynamic quantities which are impossible to study directly. 

Fig. 8. Schematic representation of the experimental arrangement for attenuated total reflection of infrared radiation in an electrochemical cell.

Fig. 1. Representation of how a number of hardware and software units can be used to generate the usual electrochemical methods which can be applied to a three-terminal or a two-terminal electrochemical cell or device via a suitable servo amplifier (potentiostat).

Fig. 9 is an electrical representation of an electrochemical cell with a semiconductor working electrode and metal counter electrode. 

From an electronic standpoint, an electrochemical cell can be regarded as a network of impedances like those shown in the equivalent circuit of Figure 15.4.1a, where Z and Z k represent the interfacial impedances at the counter and working electrodes, and the solution resistance is divided into two fractions, R and R, depending on the position of the reference electrode s contact with the current path (see Section 1.3.4). This representation can be distilled further into that of Figure 15.4. IZ . 

Figure 5.21. Schematic representation of a thin-layer electrochemical cell (A) and a wall-jet electrochemical cell (B). AUX = auxiliary electrode, REF = reference electrode and WE = working electrode.

In the case where the ionic species in the aqueous electrolyte are fairly hydrophilic and the organic phase features hydrophobic ions, the liquid]liquid junction behaves similarly to an ideally polarizable metal electrode. Under this condition, the Galvani potential difference can be effectively controlled by a four-electrode potentiostat [4,5]. A schematic representation of a typical electrochemical cell is shown in Fig. 1 [6]. Cyclic voltammo-grams illustrating the potential window for the water] 1,2-dichloroethane (DCE) interface for various electrolytes are also shown in Fig. 1. In the presence of bis(triphenylpho-sphoranylidene)ammonium hexafluorophosphate (BTPPA PFe) the supporting electrolyte in DCE, the potential window is limited to less than 200 mV due to the hydrophilicity of the anion. Wider polarizable potential ranges are obtained on replacing... 

Fig.II.1.11 (a)RC representation of the simplest equivalent circuit for an electrochemical cell, (b, c) Electrode configuration with dashed lines indicating the flow of current accompanied by potential gradients through the solution phase...

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