|Molar mass||133.0688 g/mol|
|Boiling point||1,200 °C (2,190 °F; 1,470 K) sublimates|
|Crystal structure||Rutile (tetragonal), tP6|
|Space group||P42/mnm, No. 136|
|Octahedral (RuIV); trigonal planar (O2−)|
|EU Index||not listed|
|Supplementary data page|
|Refractive index (n),
Dielectric constant (εr), etc.
|UV, IR, NMR, MS|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
Ruthenium(IV) oxide (RuO2) is a black chemical compound containing the rare metal ruthenium and oxygen. The most often used O2 catalyst is ruthenium(IV) oxide; however, care must be taken since hydrates of this oxide exist.
Structure and physical properties
Ruthenium(IV) oxide is a (nearly black) purple crystalline solid at room temperature. The hydrates of RuO2 have a blue color to them.
Ruthenium oxide has great capacity to store charge when used in aqueous solutions. Average capacities of ruthenium(IV) oxide have reached 650 F/g when in H2SO4 solution and annealed at temperatures lower than 200 °C. In attempts to optimise its capacitive properties, prior work has looked at the hydration of ruthenium oxide, its crystallinity and particle size.
There are various ways in preparing ruthenium(IV) oxide. The following processes described below are for preparing RuO2 as a film.
2. The pyrolysis, or heating of ruthenium halides, suitably deposited on the substrate by spraying on the heated substrate a solution of the halide . The most commonly used halide is ruthenium(III) chloride to form RuO2.
This technique has in fact been developed by Schafer for the preparation of nearly stoichiometric RuO2 single crystals.
Both process follow the same reaction mechanism:
- Ru+(IV) + O2 (heat)→ RuO2
High temperature flashes of heat up to 1500 °C can remove all oxides and contaminants, and form a new oxide layer on the ruthenium.
3. Another way to prepare RuO2 is through electroplating. Films can be electroplated from a solution of RuCl3.xH2O. Pt gauze was used as the counter electrode and Ag/AgCl as the reference electrode.
Ruthenium(IV) oxide is a versatile catalyst and doping agent. Hydrogen sulfide can be split by light by using a photocatalyst of CdS particles doped with ruthenium(IV) oxide loaded with ruthenium dioxide. This may be useful in the removal of H2S from oil refineries and from other industrial processes. The hydrogen produced could be used to synthesize ammonia, methanol, and possibly fuel a future hydrogen economy.
Ruthenium (IV) oxide is being used as the main component in the catalyst of the Deacon process which produces chlorine by the oxidation of hydrogen chloride.It can be also used as active material in supercapacitor because has very high charge transfer capability.
Ruthenium oxide resistors can be used as sensitive thermometers in the temperature range .02<T<4K.
RuO2 by itself is a poor catalyst because without the presence of a hydrate its surface area is greatly decreased. To get pure ruthenium(IV) oxide, it needs to be annealed at 900 °C. The best catalyst for electrochemical processes is to have some hydrate present, but not a completely hydrous one. RuO2 can be used as catalyst in multiple reactions. Such noteworthy reactions are the Fischer-Tropsch process and fuel cells.
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