Hydroxides gold metallizations

A preformed support may be impregnated with this HAuCU and then treated with a reducing agent. Alternatively, when the pH of a mixture of HAuCU and various metal ions is raised, gold hydroxide and metal hydroxide coprecipitate. Drying, calcination, and reduction of this mixture provide Au(0) supported upon a metal oxide. Suitable reducing agents include H2, BH4, citrate, and ascorbate. Permutations of... 

Under alkaline conditions, oxides and hydroxides of metals including silver, gold, copper (cuprous and cupiic oxides), mercury, bismuth and niekeF are. reduced to metals by foimaldehyde. The quantitative reduction of freshly precipitated bismuth hydroxide by excess formaldehyde in the presence of sodium hydroxide affords a method for the determination of bismuth . 

Metals and Metallic Ions. Under appropriate conditions, ozone oxidizes most metals with the exception of gold and the platinum group. When oxidized by ozone, heavy metal ions, such as Fe and Mn , result in the precipitation of insoluble hydroxides or oxides upon hydrolysis (48—50). Excess ozone oxidizes ferric hydroxide in alkaline media to ferrate, and Mn02 to MnO. ... 

Rubidium metal alloys with the other alkaU metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double haUde salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and 2iac. These complexes are generally water iasoluble and not hygroscopic. The soluble mbidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide. 

Pla.tinum, Platinum plating has found appHcation in the production of platinised titanium, niobium, or tantalum anodes which are used as insoluble anodes in many other plating solutions (see Metalanodes). Plating solutions were often based on platinum "P" salt, which is diamminedinitroplatiniim (IT). A dinitroplatinite sulfate—sulfuric acid bath has been used to plate direcdy onto titanium (129). This bath contains 5 g/L of the platinum salt, pH adjusted to 2.0 with sulfuric acid. The bath is operated at 40°C at 10—100 A/m. Other baths based on chloroplatinic acid have been used in both acid and alkaline formulations the acid bath uses 20 g/L of the platinum salt and 300 g/L hydrochloric acid at 65° C and 10—200 A/m. The alkaline bath uses 10 g/L of the platinum salt, 60 g/L of ammonium phosphate and ammonium hydroxide to give a pH of 2.5—9.0. The alkaline bath can be plated directly onto nickel-base alloys acid baths require a gold strike on most metals. 

Heating with the following solids, their fusions, or vapours (a) oxides, peroxides, hydroxides, nitrates, nitrites, sulphides, cyanides, hexacyano-ferrate(III), and hexacyanoferrate(II) of the alkali and alkaline-earth metals (except oxides and hydroxides of calcium and strontium) (b) molten lead, silver, copper, zinc, bismuth, tin, or gold, or mixtures which form these metals upon reduction (c) phosphorus, arsenic, antimony, or silicon, or mixtures which form these elements upon reduction, particularly phosphates, arsenates,... 

The possible strategies are coprecipitation to prepare mixed hydroxides or carbonates [5], cosputtering of gold and the metal components of the supports by Ar containing O2 to prepare mixed oxides [23], and amorphous alloying to prepare metallic mixed precursors [24]. These... 

The approach comprises deposition-precipitation (DP) of Au(OH)3 onto the hydroxide surfaces of metal oxide supports from an alkaline solution of HAUCI4 [26] and grafting of organo gold complexes such as dimethyl gold (Ill)acetylacetonate (hereafter denoted as Au acac complex) [27] and Au(PPh3)(N03) [28] either in gas and liquid phase are advantageous in that a variety of metal oxides commercially available in the forms of powder, sphere, honeycomb can be used as supports. 

The oxidation of hydroxide ion in acetonitrile at copper, silver, gold, and glassy-carbon electrodes has been characterized by cyclic voltammetry. In the absence of bases the metal electrodes are oxidized to their respective cations (Cu+, Ag+, and Au+) at potentials that range from -0.2V vs. SCE for Cu to +1.3 V for Au. At glassy carbon OH is oxidized to 0 - (+0.35 V vs SCE) and then to... 

Klingler and co workers—impact of metal coordination on the formate pathway. Klingler and coworkers114,125 carried out studies on the cation reactivity of formate in solution at 180 °C, 7.8 mol/L of H20 with the solvent triethylene glycol, and the formate concentration was varied. It was noted that formic acid produced from the carbonylation of water is catalyzed by hydroxide anion, and rapidly builds up to close to equilibrium concentration levels under these conditions, so that they had to use gold plated stainless steel autoclaves. They obtained a first order dependency of the water-gas shift reaction rate (i.e., H2 evolution rate) with formate concentration. As a control experiment, they added metal pentacarbonyl iron to the reactor, and observed no additional rate increase, indicating that the water-gas shift... 

An even more serious problem can arise when dissolved species expected to predominate at high temperatures are undetectable at 25°C or are only present at concentrations which are too low for them to be adequately characterized thermodynamically. Examples are certain transition metal chloro-complexes (9,10) and mixed complexes of such metals with hydroxide and another ligand (11,12). Thus it seems that chloride complexing so alters the aqueous chemistry of copper and gold that supposedly inert gold components in autoclaves are reversibly oxidized by Cull (10) and it is likely that mixed oxine and hydroxy complexes of Fell contribute considerably to the gross under-estimation (by a factor of up to 10 ) of magnetite solubility in oxine (12,14). 

Our approach utilized the metals gold, platinum, then later gold, platinum, and nickel electroplated in succession because the catalytic decomposition of hydrogen peroxide reaction we tested was most efficiently catalyzed with platinum.After fabrication of the nanowires they were freed by removing the conductive silver backing with nitric acid and the sacrificial template with a strong base, sodium hydroxide. Then nanorods were washed with deionized water and ultracentrifuged to achieve a neutral pH. 

Heating the hydroxide at about 140°C yields gold(lll) oxide which on further heating decomposes to metallic gold and oxygen ... 

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