Sulfide electrodes

These reactions were seen during cyclic voltammetry on all three cathodes, (Fig. 33). Note in Fig. 33a the relatively small currents representing the reduction and oxidation of Eq. (35). But in Fig. 33b the much larger currents are due to the electrode sulfidation and reduction, Eq. (39). All sulfided electrodes were analyzed by X-ray... 

De Marco [285] evaluated three different types of copper (II) ion-selective electrodes. The copper sulfide electrode was found to be oxidised, whereas the copper selenide and copper sulfide electrodes were found to have chloride ion interference at copper (II) activities exceeding 10 8 M. 

The ion that determines the p>otential of the compact layer is called the potential-determining ion. In cases in which the potentied of compact layer is determined by the dissociation reaction of adsorbed hydroxyl groups, the potential -determining ions are hydrated protons or hydroxide ions. For cadmium sulfide electrodes, the potential-determining ions are not hydrated protons but hydrated sulfide ions the iso-electric point is at the sulfide ion concentration of 4 x 10 M [Ginley-Butler, 1978]. 

Minoura H, Tsuiki M (1978) Anodic reaction of several reducing agents on illuminated cadmium sulfide electrode. Electrochim Acta 23 1377-1382... 

Elemental composition Na 58.93%, S 41.07%. An aqueous solution is analyzed to determine sodium content. Also, an aqueous solution may be analyzed for sulfide by methylene blue colorimetric test or by iodometric titration (APHA, AWWA, and WEF. 1999. Standard methods for the Examination of Water and Wastewater, 20 ed. Washington, DC American Pubhc Health Association). The methylene blue test is based on reacting sulfide, ferric chloride and dimethyl-p-phenylenediamine to produce methylene blue. Also, sulfide can be measured by using a sdver-sdver sulfide electrode. Quahtatively, sulfide may be identified from the hberation of H2S on treatment with acid. The H2S turns the color of paper soaked with lead acetate black (See Hydrogen Sulfide). 

Molybdenum selenide and molybdenum sulfide electrodes shall demonstrate the influence of different surface orientation on photoredox reactions. Figure U represents the crystal structure of MoS where one can immediately see that on the van der Waals-sur-face exclusively sulfur atoms are exposed to the contact with the electrolyte. They should behave very differently from any other surface where the molybdenum atoms are not so well shielded from interaction with the electrolyte solution. 

Figure 7 shows another set of examples for a molybdenum sulfide electrode (JJ>). Current voltage curve No. 1 gives the result for a smooth electrode surface cleaved along the van der Waals-... 

Effects of Temperature on Excited-State Descriptions of Luminescent Photoelectrochemical Cells Employing Tellurium-Doped Cadmium Sulfide Electrodes... 

In the light of common parallelisms between catalysis and electrocatalysis, it is interesting to note that Co and Mo are used in catalytic processes of hydrodesulfurization [450], The activity of sulfide electrodes changes with time [439, 442, 446]. Normally, there is an initial period during which the overpotential decreases, then it increases again or levels off at a constant activity. The initial improvement is interpreted in various ways but it is generally attributed to some stabilization of the electrode surface (Fig. 23). It seems that a hydride phase is formed initially [442],... 

The thermodynamic stability constant of silver sulfadiazine in water has been measured by Boelema et al. (20). They made use of a microcomputer-controlled titrator and measured simultaneously the pH value with a Radiometer G2040C glass electrode and the silver ion concentration with an Orion research 941600 ion-selective silver sulfide electrode. The measured stability constant and standard deviation were logK=3.62i 0.05 n = 9, temperature 25°C, ionic strength 0.1 (sodium nitrate). The calculated conditional stability constant log K at pH 7.4 was 3.57. 

Promising new analytical tools are further enzymatic analysis, coated wire electrodes, high-pressure liquid chromotography, sulfide electrode use, and use of computers for data storage and retrieval and for monitoring laboratory instrumentation. 

Intercalation electrodes may include either carbon electrodes or transition metal oxide and sulfide electrodes, which intercalate with solution components such as metal cations. The most important example is intercalation of lithium ions with many types of carbonaceous materials at low potentials (0-1.5 V versus Li/Li+)... 

Sulfacetamide and other sulfonamides in pharmaceutical dosage forms have been determined with a silver sulfide electrode over the concentration range lO -lO 1 M. The sulfonamide is dissolved in dimethylformamide, 0.01 N silver nitrate is added, the solution filtered, and the resulting precipitate washed and the excess silver nitrate determined by potentiometric titration with 0.01 N sodium chloride (67,68). 

Tests for S include the antimony test, silver-silver sulfide electrode test and the lead acetate paper and silver foil tests. In the antimony test, the color produced by treating a 200 ml test sample with 0.5 ml saturated potassium antimony tartrate and 0.5 ml 6 N HCl is compared with colors produced when solutions containing known amounts of S are treated in the same way. In the silver-silver sulfide electrode test, the test sample is diluted 1 1 with an alkaline solution of an oxidizing agent and the electrode potential relative to a double-junction reference electrode is measured. 

Nonequilibrium SO2 sensors have been reported using a sodium ion-conducting electrolyte (Na5DySi40i2) with sulfide electrodes. Among a large number of binary and mixed sulfides, CdS provides the best response [337, 338],... 

Souda. N. and Shimizu, Y. (2003) Sensing properties of solid electrolyte SO2 sensor using metal-sulfide electrode. J. Mater. Sci., 38 (21), 4301-5. 

Sulfide and pH measures were not always made on the same gravity cores used for Fe and Mn pore-water analyses, but the general values of these parameters are relatively predictable deep in the sediment at each station based on other cores. These are listed in Appendix B of Part I along with pore-water analyses. Sulfide levels are highest at FOAM (Gold-haber et al., 1977) and lowest at DEEP where they are below the detection limit of a sulfide electrode, pS s 16, in the gravity-core samples (but not in the box cores). 

High-performance lithium-sulfur cells are being developed for use in off-peak energy storage batteries in electric utility networks. The cells, which operate at 400°C, consist of a lithium electrode, a sulfur or sulfide electrode, and molten LiCl-KCl electrolyte. The chemistry of the lithium electrode is relatively straightforward. However, the electrochemical reactions at the sulfur electrode involve the formation of several intermediate species that are sufficiently soluble in the electrolyte to limit the lifetime and capacity of the cells. Although this effect can be decreased with soluble additives such as arsenic or selenium in the sulfur, a more promising solution appears to be the use of metal sulfides, rather than sulfur, as the active material in the positive electrode. 

Metal Sulfide Electrodes for Secondary Lithium Batteries... 

Extensive testing of metal sulfide electrode materials was performed in cells of the type shown in Figure 1. The metal sulfide electrode case and current take-off rod were made of dense graphite to avoid any contact and possible contamination of the active material by metallic constituents. The active material (metal sulfide powder in a porous graphite matrix or a mixture of metal sulfide and graphite powder) was contained in the cavity (2.5 cm in diameter X 0.6 cm deep) of the dense graphite electrode case. A porous ceramic separator was placed over the active material and secured with high purity alumina pins. 

Two long-term tests have been performed with copper sulfide electrodes, one in a small investigative cell of the type shown in Figure 1, the other in a sealed 25-W-hr cell which will be described later. The starting active material in both cells was CuS. In both cases, the lithium electrodes consisted of porous metal plates impregnated with molten lithium metal. The electrolyte was the LiCl-KCl eutectic salt mixture, saturated with Li2S and maintained at 380-400°C. 

Table III. Copper Sulfide Electrode Cycling Test Histories...

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