Ruthenium oxide electrode

The total capacity of a ruthenium oxide electrode [the usual double-layer capacity plus the pseudocapacity of reaction (21.4)] is rather high (i.e., several hundred F/g), even more than at the electrodes of carbon double-layer capacitors. The maximum working voltage of ruthenium oxide pseudocapacitors is about 1.4 V. 

Kim, H. K S. H. Cho, Y. W. Ok, T. Y. Seong, and Y. S. Yoon. 2003. All solid-state rechargeable thin-fibn microsupercapacitor fabricated with tungsten cosputtered ruthenium oxide electrodes. Journal of Vacuum Science and Technology B Microelectronics and Nanometer Structures 21 949-952. 

The number of studies which utilize ionic liquid electrol54e in redox capacitor system is still small, probably due to the difficulty to reproduce the pseudo-capacitive reaction in ionic liquid media. While the principle of pseudo-capacitance of conductive polymer electrodes permits to utilize ionic liquid electrolytes, high viscosity and rather inactive ions of ionic liquid may make their pseudo-capacitive reaction slow. The combination of nanostmctured conductive polymer electrode and ionic liquid electrolyte is expected to be effective [27]. It is far difficult that ionic liquids are utilized in transition metal-based redox capacitors where proton frequently participates in the reaction mechanisms. Some anions such as thiocyanate have been reported to provide pseudo-capacitance of manganese oxide [28]. The pseudo-capacitance of hydrous ruthenium oxide is based on the adsorption of proton on the electrode surface and thus requires proton in electrolyte. Therefore ionic liquids having proton have been attempted to be utilized with ruthenium oxide electrode [29]. Recent report that 1,3-substituted imidazolium cations such as EMI promote pseudo-capacitive reaction of mthenium oxide is interesting on the viewpoint of the establishment of the pseudo-capacitive system based on chemical nature of ionic liquids [30]. 

Jeong, M.-G. Zhuo, K. Cherevko, S. Kim, W.-J. Chung, C.-H. Facile preparation of three-dimensional porous hydrous ruthenium oxide electrode for supercapacitors. J. Power Sources 2013, 244, 806-811. 

Ion implantation has also been used for the creation of novel catalyticaHy active materials. Ruthenium oxide is used as an electrode for chlorine production because of its superior corrosion resistance. Platinum was implanted in mthenium oxide and the performance of the catalyst tested with respect to the oxidation of formic acid and methanol (fuel ceU reactions) (131). The implantation of platinum produced of which a catalyticaHy active electrode, the performance of which is superior to both pure and smooth platinum. It also has good long-term stabiHty. The most interesting finding, however, is the complete inactivity of the electrode for the methanol oxidation. 

Because of the considerable corrosivity of chlorine toward most metals, anodic chlorine evolution can only be realized for a few electrode materials. In industry, graphite had been used primarily for this purposes in the past. Some oxide materials, manganese dioxide for instance, are stable as well. At present the titanium-ruthenium oxide anodes (DSA see Chapter 28) are commonly used. 

Oxidation States of Ruthenium Oxide and Ru-Based Electrodes. 95... 

For Cl2 or 02 evolution the stability of ruthenium based electrodes is not sufficient on a technical scale. Therefore the possibility of stabilizing the ruthenium oxide without losing too much of its outstanding catalytic performance was investigated by many groups. For the Cl2 process, mixed oxides with valve metals like Ti or Ta were found to exhibit enhanced stability (see Section 3.1), while in the case of the 02 evolution process in solid polymer electrolyte cells for H2 production a mixed Ru/Ir oxide proved to be the best candidate [68, 80]. 

Rare, shiny, and lightest metal of the platinum group. Hardens platinum and palladium. The presence of 0.1 % of ruthenium in titanium improves its resistance to corrosion 100-fold. The spectacular catalytic properties of ruthenium are used on industrial scales (hydrogenations, sometimes enan-tioselective, and metathesis). Titanium electrodes coated with ruthenium oxide are applied in chlorine-alkaline electrolysis. Suitable for corrosion-resistant contacts and surgical instruments. 

Another useful bimetallic for fuel cell electrodes is Pt/Ru. Ruthenium is readily oxidized to Ru02 by calcination after it is impregnated. The PZC of ruthenium oxide is unknown. Propose a comprehensive sequence of experiments with which the SEA method can be applied for the synthesis of a Pt/Ru bimetallic catalyst supported on carbon. The goal is to have intimate contact between the Pt and Ru phases in the final, reduced catalyst. 

The diffusion-limited electrochemical oxidation of V-nitrosamines in an aqueous pH 1.5 buffer was demonstrated at a GCE coated with a film of mixed valence ruthenium oxides, stabilized by cyano crosslinks. This electrode was used in a potentiostatic amperometric detector for FIA and HPLC, to allow the determination of representative N-nitrosamines (278a, 278c and 278d) for 278c, LOD was 10 nM and RSD 2% at 0.80 pM... 

J.-M. Zen, C.-W. Wang, Determination of Dissolved Oxygen by Catalytic Reduction on a Nafion /Ruthenium Oxide Pyrochlore Chemically Modified Electrode, J. Electroanal. Chem. 368 (1994) 251—256. 

An improved adsorption of DNA bases has been observed at a chemically modified electrode based on a Nafion/ruthenium oxide pyrochlore (Pb2Ru2-x FhxOj-y modified GC (CME). Nafion is a polyanionic perfiuorosulfonated ionomer with selective permeability due to accumulation of large hydrophobic cations rather than small hydrophilic ones. The Nafion coating was demonstrated to improve the accumulation of DNA bases, while the ruthenium oxide pyrochlore proved to have electrocatalytic effects towards the oxidation of G and A. The inherent catalytic activity of the CME results from the Nafion-bound oxide surface being hydrated. The catalytically active centers are the hydrated surface-boimd oxy-metal groups which act as binding centers for substrates [50]. 

The electrochemical behavior of chlorpromazine hydrochloride in 0.2M H2SO4 was studied by cyclic and linear sweep voltammetry at an oxidized and a non-oxidized ruthenium wire electrode [173]. Preparation of a stable and permanent coating of RuOj on the electrode was very time-consuming, but the resulting curves were highly reproducible. The... 

In nonbiological applications, mixed ruthenium complexes of bipyridyl ligands and substituted pteridine diones have been used as components of photovoltaic cells <2002JPH167>. When fabricated into sol-gel processed titanium oxide electrodes, these complexes achieved photocurrent conversion efficiency in the range 20 8%. 

Electronic Applications. The PGMs have a number of important and diverse applications in the electronics industry (30). The most widely used are palladium and ruthenium. Palladium or palladium—silver thick-film pastes are used in multilayer ceramic capacitors and conductor inks for hybrid integrated circuits (qv). In multilayer ceramic capacitors, the termination electrodes are silver or a silver-rich Pd—Ag alloy. The internal electrodes use a palladium-rich Pd—Ag alloy. Palladium salts are increasingly used to plate edge connectors and lead frames of semiconductors (qv), as a cost-effective alternative to gold. In 1994, 45% of total ruthenium demand was for use in ruthenium oxide resistor pastes (see ELECTRICAL CONNECTORS). 

Abruna, HD, Meyer, T3, Murray, RW, Chemical and Electrochemical Properties of 2,2 —bipyridyl Complexes of Ruthenium Covalently Bound to Platinum Oxide Electrodes. 

The screen-printing paste is made up in the manner described in Section 4.2.2 and the patterns printed. The heater element and its leads would typically be platinum and the interdigitated electrodes gold. As illustrated below (Fig. 4.49) the heater might also be a composition based on ruthenium oxide (see Section 4.2.2). The contacting tabs are also screen-printed gold. 

Papadatos, E, Consiglio, S., Skordas, S., Eisenbraun, E. T., Kaloyeros, A. E., Peck, J., Thompson, D. and Hoover, C. (2004), Chemical vapor deposition of ruthenium and ruthenium oxide thin films for advanced complementary metal-oxide semiconductor gate electrode applications. J. Mater. Res., 19(10) 2947-2955. 

Munich An integrated process for making chlorine dioxide from hydrochloric acid. Sodium chlorate is made electrochemically from sodium chloride, and this is reduced with hydrochloric acid. Developed from the Kesting process by H. Frohler and E. Rossberger at the Elektrochemische Werke Munchen, Germany, and first commercialized in 1974. The essential improvement over the Resting process is the use of titanium electrodes coated with ruthenium oxide for the electrolytic... 

Substantial amounts of chloride are present in the fixed ruthenium oxide-based films, e.g. about 4% for a preparation temperature of 400°C [194, 195]. The chlorine content has been observed to decrease slightly on going to the external surface as indicated by, for example, secondary ion mass spectrometry [196]. The exact location of chlorine in the bulk lattice is somewhat unclear at present. Oxygen content has been found to increase sharply over the last few monolayers at the external surface, as shown by SIMS [196] and XPS measurements for powders [197] and films [198], There is now evidence from several groups that suggests the existence of some Ru03 in the surface regions of ruthenium dioxide electrodes [196-200]. 

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