Ruthenium coatings

These results, as well as similar findings obtained for CO adsorbed at ruthenium-coated gold (3d), are of relevance to the mechanism of CO electrooxidation since they indicate that a significant fraction of the CO adsorbed at potentials where reaction proceeds is modified substantially by the early stages of metal oxidation. This suggests that adsorbed 0 or OH may be responsible for CO electrooxidation on these surfaces, although such sites admittedly may not be electrocatalytic in nature. 

Leung, L.-W.H. and Weaver, M.J. (1988) Adsorption and electrooxidation of carbon monoxide on rhodium- and ruthenium-coated gold electrodes as probed by surface-enhanced... 

Wilke, T., Gao, X., Takoudis, C.G., and Weaver, M.J. (1991) Surface-enhanced Raman spectroscopy as a probe of adsorption at transition metal-high-pressure gas interfaces NO, CO, and oxygen on platinum-, rhodium-, and ruthenium-coated gold. Langmuir, 7, 714-721. 

Electrocatalysis at metal electrodes in aqueous (1.2) and non-aqueous ( ) solvents, phthalocyanine ( ) and ruthenium ( ) coated carbon, n-type semiconductors (6.7.8),and photocathodes (9,10) have been explored in an effort to develop effective catalysts for the synthesis of reduced products from carbon dioxide. The electrocatalytic and photocatalytic approaches have high faradaic efficiency of carbon dioxide reduction (1,6). but very low current densities. Hence the rate of product formation is low. Increasing current densities to provide meaningful amounts of product, substantially reduces carbon dioxide reduction in favor of hydrogen evolution. This reduction in current efficiency is a difficult problem to surmount in light of the probable electrostatic repulsion of carbon dioxide, or the aqueous bicarbonate ion, from a negatively charged cathode (11,12). 

Walaszek, B., Yeping, X., Adamczyk, A. et al. 2009. H-solid-state-NMR study of hydrogen adsorbed on catalytically active ruthenium coated mesoporous silica materials. Solid State Nucl. Magn. Reson. 35 164-171. 

The successful use of ruthenium-coated porous Ti electrodes coupled with the benefits of adopting back-flow configuration [43] is strongly suggestive that there are combinations of physical architecture, flow configurations and electrode functionalization with good operational capability stiU awaiting discovery. 

Figure 6.6 Top, inverted opal silicon carbide monoliths with 7,2-pm pore size middle, fracture profile of a ruthenium coated silicon carbide monolith bottom, integrated ceramic monolith with alumina housing five ceramic monoliths are integrated and alumina inlet and outlet tubes connected [460],...

Nanospheres of ruthenium coated with platinum serve as a catalyst for the purification of hydrogen fuel (see text Fig. 7.46). 

Miscellaneous. Ruthenium dioxide-based thick-film resistors have been used as secondary thermometers below I K (92). Ruthenium dioxide-coated anodes ate the most widely used anode for chlorine production (93). Ruthenium(IV) oxide and other compounds ate used in the electronics industry as resistor material in apphcations where thick-film technology is used to print electrical circuits (94) (see Electronic materials). Ruthenium electroplate has similar properties to those of rhodium, but is much less expensive. Electrolytes used for mthenium electroplating (95) include [Ru2Clg(OH2)2N] Na2[Ru(N02)4(N0)0H] [13859-66-0] and (NH 2P uds(NO)] [13820-58-1], Several photocatalytic cycles that generate... 

Recently it has been shown that the oxides of the platinum metals can have a higher corrosion resistance than the metals themselves , and have sufficient conductivity to be used as coatings for anodes, e.g. with titanium cores. Anodes with a coating of ruthenium dioxide are being developed for use in mercury cells for the electrolysis of brine to produce chlorine , since they are resistant to attack if in contact with the sodium-mercury amalgam. 

The composition of the mixed metal oxide may well vary over wide limits depending on the environment in which the anode will operate, with the precious metal composition of the mixed metal oxide coating adjusted to favour either oxygen or chlorine evolution by varying the relative proportions of iridium and ruthenium. For chlorine production RuOj-rich coatings are preferred, whilst for oxygen evolution IrOj-rich coatings are utilised. ... 

The most widely used methods for the application of coatings of gold, silver and the platinum group metals (platinum, palladium, rhodium, iridium, ruthenium, osmium) to base metals are mechanical cladding and electroplating. 

Ruthenium, iridium and osmium The use of a fused cyanide electrolyte is the most effective means for the production of sound relatively thick coatings of ruthenium and iridium, but this type of process is unattractive and inconvenient for general purposes and does not therefore appear to have developed yet to a significant extent for industrial application. This is unfortunate, since these metals are the most refractory of the platinum group and in principle their properties might best be utilised in the form of coatings. However, several interesting improvements have been made in the development of aqueous electrolytes. 

Platinum Platinum-coated titanium is the most important anode material for impressed-current cathodic protection in seawater. In electrolysis cells, platinum is attacked if the current waveform varies, if oxygen and chlorine are evolved simultaneously, or if some organic substances are present Nevertheless, platinised titanium is employed in tinplate production in Japan s. Although ruthenium dioxide is the most usual coating for dimensionally stable anodes, platinum/iridium, also deposited by thermal decomposition of a metallo-organic paint, is used in sodium chlorate manufacture. Platinum/ruthenium, applied by an immersion process, is recommended for the cathodes of membrane electrolysis cells. ... 

The largest uses of platinum group metals in electronics are ruthenium for resistors and palladium for multilayer capacitors, both applied by thick film techniques . Most anodes for brine electrolysis are coated with mixed ruthenium and titanium oxide by thermal decomposition . Chemical vapour deposition of ruthenium was patented for use on cutting tools . 

Both of these elements are silver-white lustrous metals with high melting (ruthenium 2310°C, osmium 3900°C) and boiling (3900 and 5510°C, respectively) points. As usual, the 5d metal is much more dense (ruthenium 12.45, osmium 22.59gem-3) both adopt hep structures osmium is the densest metal known. The metals are unreactive, insoluble in all acids, even aqua regia. Ruthenium tends to form a protective coating of the dioxide and is not attacked by oxygen below 600°C nor by chlorine or fluorine below... 

Ruthenium nowadays finds many uses in the electronics industry, particularly for making resistor tracks. It is used as an ingredient in various catalysts and, importantly, in electrode materials, e.g. Ru02-coated titanium elements in the chloralkali industry. Osmium tetroxide is a very useful organic oxidant and, classically, is used as a tissue stain. Both elements are employed in making certain platinum alloys. 

In the theoretical treatment of ion exchange polymers the roles of charge propagation and of migration of ions were further studied by digital simulation. Another example of proven 3-dimensional redox catalysis of the oxidation of Ks[Fe(CN)5] at a ruthenium modified polyvinylpyridine coated electrode was reported... 

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. 

Figure 6. Tip of the 20-pm tip of a fiber optic oxygen microsensor. The tip is coated with a ormosil-type of sol-gel doped with a ruthenium indicator for oxygen that display red luminescence. The sensor measures its decay time as a function of oxygen partial pressure.

The 02-sensing materials based on spin-coated n-octyl-triethoxysilane (Octyl-triEOS) / tetraethylorthosilane (TEOS) composite xerogel films was synthesized and investigated99. These sensors were based on the O2 quenching of tris(4,7-diphenyl-l,10-phenanthroline)ruthenium (II)... 

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