Electrochemical window reference electrode

Figure 3.6-1 The electrochemical window of 76-24 mol % [BMMIM][(CF3S02)2N]/Li [(Cp3S02)2N] binary melt at a) a platinum working electrode (solid line), and b) a glassy carbon working electrode (dashed line). Electrochemical window set at a threshold of 0.1 mA cm. The reference electrode was a silver wire immersed in 0.01 m AgBp4 in [EMIM][BF4] in a compartment separated by a Vicor frit, and the counter-electrode was a graphite rod.

Ideally, one would prefer to compare anodic and cathodic potential limits instead of the overall ionic liquid electrochemical window, because difference sets of anodic and cathodic limits can give rise to the same value of electrochemical window (see Figure 3.6-1). However, the lack of a standard reference electrode system within and between ionic liquid systems precludes this possibility. Gonsequently, significant care must be taken when evaluating the impact of changes in the cation or anion on the overall ionic liquid electrochemical window. 

Table 7 lists the electrochemical windows or the anodic stability limits of several nonaqueous electrolytes, or their anodic stabilty, the reference electrodes Rref used, the working electrode material Ew, the experimental conditions, and the references. It shows the following features ... 

SXS measurements. (A) Single-crystal disk electrode, (B) Pt counter electrode, (C) Ag/AgCl reference electrode, (D) Mylar window, (E) electrolyte solution, (F) inlet for electrolyte solution, (G) outlet for electrolyte solution, (H) cell body, (1) micrometer, (J) electrode holder, (K) outer chamber, (b) Cell configuration for electrochemical measurement, (c) Cell configuration for SXRD measurement. (From Kondo et al., 2002, with permission from Elsevier.)... 

Figure 2.105 Optically transparent thin layer electrochemical (OTTLE) cell. A = PTFE cell body, B = 13 x 2 mm window, (C and E) = PTFE spacers, D = gold minigrid electrode, F = 25 mm window, G = pressure plate, H = gold working electrode contact, 1 = reference electrode compartment, J = silver wire, K = auxiliary electrode and L = solution presaturator. From Ranjith...

The electrochemical window of pure molten cryolite has not been expressly stated, but a voltammogram of purified cryolite recorded at a graphite working electrode exhibits very little residual current over the range of potentials extending from 0.4 to -1.9 V vs. a nickel wire quasi-reference electrode [7]. Physical property data for molten cryolite and phase equilibria for the AlF3-NaF melt system have been summarized [31,32]. The extremely high temperature of cryolite places severe constraints on the materials that can be used for cells. Platinum and boron nitride are the materials of choice. 

Figure 17.10 Gas-tight transmission cell for IR spectroelectrochemistry in moderate-melting salts (A) optically transparent electrode (OTE) port, (B) reference electrode and auxiliary electrode ports, (C) Si windows, (D) vacuum valve, (E) light path. [From P. A. Flowers and G. Mamantov, J. Electrochem. Soc. 136 2944 (1989), with permission.]...

The vertical axis is in volts relative to the saturated calomel reference electrode (SCE). Photoemission in aqueous media is best performed in the electrochemical window, between the hydrogen and oxygen evolution redox potentials, where small dc currents allow easier detection of the photoemission current. Protons are used for scavenging the... 

For electrochemical work it is important to know the limiting potentials that may be applied in oxidative, anodic, or reductive, cathodic, scans of solutions in which solutes can undergo redox reactions without the solvent being oxidized or reduced. These limits constitute the electrochemical window for the solvent. However, the breadth of this window, in terms of the applicable voltages, depends not only on the solvent itself, but also on the material of the working electrode involved, the reference electrode against which the potentials are measured, and the nature of the supporting electrolyte present. 

Figure 15 A cell for in situ single internal reflectance spectroscopy (1) working electrode—an NaCl optical window covered by a thin Pt deposited layer, (2) reference electrode, (3) counterelectrode, (4) polyethylene cell body, (5) space for solution, (6) electrical contact to the working electrode—a thin nickel foil, (7) O ring, (8) polyethylene cover, (9) brass holder for the optical window, (10) bolts that hold the cell [44]. (Reprinted with copyright from The Electrochemical Society Inc.)...

Figure 4.2 Electrochemical windows of EMI-BF4 estimated with various reference electrodes. The arrow shows the position of a certain redox material such as ferrocene (the position is virtually indicated).

Figure 4.6 Electrochemical windows of chloroaluminate system with a correction by the ferrocene internal reference. Original data were measured with the different REs. Solid N = 0.67 broken N = 0.60. Working electrode GC (glassy carbon) W (tungsten) Pt (platinum).

The rather narrow electrochemical window of water, limited by the discharge of hydrogen and oxygen, has stimulated the use of nonaqueous solvents for electrochemical reactions. Procedures for measuring and reporting electrode potentials in nonaqueous solvents are presented in reference [128]. The solvent influence on the redox properties of cations and anions has been reviewed [172], as have applications of ion-selective electrodes in nonaqueous solvents [129] and the influence of nonaqueous solvents on the polarographic half-wave potentials of cations [173]. 

Whereas 1.2 V is the fundamental electrochemical window in aqueous solutions, more than 3 V is available in some of the currently discussed systems. As a concrete example, A1 can be electrochemically deposited from AljCl, at -0.4 V with an A1 electrode taken as reference. The evolution of Clj occurs at +2.5 V against the same reference electrode. Thus, the window is 2.5 - (-0.4) = 2.9 V. 

Fig. 10.8 Thin-layer electrochemical cell used in SNIFTIR studies and reflection optics (a) Teflon cap (b) N2 inlet (c) glass tube (d) Teflon cell body (e) port for reference electrode (f) ceramic tube (g) Pt wire counter electrode (h) single crystal working electrode (i) hemispherical ZnSe window (k) focal plane for reflection optics (m) instrument focal plane and (n) folding mirrors (From reference 16, with permission.)...

Figure 40. Electrochemical cell for in situ grazing-incidence x-ray scattering experiments. A, silver(l 11) electrode B, Ag/AgCI reference electrode C, Pt counter electrode D, polypropylene window E, O-ring F, contact to Ag electrode G, solution inlet H, solution outlet. (From Samant, M. G., Toney, M. F., et al., Phys. Rev. B. 38 10962 (1988), with permission.)...

Fig. 2. Schematic illustration of the vacuum-tight, short path length, thin-layer spectro-electrochemical cell with a doubled platinum gauze working electrode. The side view shows how the cell assembly is positioned for acquiring spectral data. The top view shows the connection of the outer RC circuit. The symbols are as follows (a) thin-layer chamber, (b) doubled platinum gauze working electrode with edge eliminator, (c) expanded platinum metal counterelectrode, (d) platinum wire auxiliary reference electrode, (e) photo window, (f) reference point, the tip of the frit, (g) asbestos disk, (h) reference frit. CE, counterelectrode post WE, working electrode post RE, Ag/AgCI, KCI reference electrode ARE, auxiliary reference electrode post RE, reference electrode post. ...

Electrochemical cell with quartz window and saturated calomel electrode as a reference electrode was used (Fig. 3). Photoelectrochemical measurements were conducted with Pl-50-1 potentiostat under illumination power density of 75 mW/cm. At first the efficiency of energy accumulation (in the form of absorbed hydrogen) was estimated from the cathode discharge curves and from the hydrogen volume released under cathode heating. The volume of hydrogen released was measured in the tailor-made setup. The discharge capacity measurements were performed in electrochemical cell with nickel counter electrode. 

These coated glasses can be used as working electrodes [optically transparent electrodes (OTE)] in standard three-electrode arrangements provided that both glass and coating are chemically and electrochemically stable and inert in the used electrolyte solution and the applied range of electrode potentials. The use of a modified infrared spectroscopy transmission cell equipped with quartz windows for UV-Vis spectroelectrochemistry has been described [18]. Platinum layers deposited onto the quartz served as an optically transparent working electrode and an additional platinum layer served as a pseudo-reference electrode. A counter electrode outside the thin layer zone (in one of the tubes used for solution supply) served as a counter... 

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