Cobalt boride

Cobalt boride
Names
IUPAC name Cobalt boride
Identifiers
CAS Number	12006-77-8
EC Number	235-722-7
PubChem CID	13628825
Properties
Chemical formula	CoB
Molar mass	69.744
Appearance	Refractory Solid
Density	7.25 g/cm³
Melting point	1,460 °C (2,660 °F; 1,730 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

Cobalt borides are inorganic compounds with the general formula Co_xB_y.^[1] The two main cobalt borides are CoB and Co₂B. These are refractory materials.

Applications

Materials science

Cobalt borides are known to be exceptionally resistant to oxidation, a chemical property which makes them useful in the field of materials science. For instance, studies suggest cobalt boride can increase the lifespan of metal parts when used as a coating, imparting surfaces with higher corrosion and wear resistance. These properties have been exploited in the field of biomedical sciences for the design of specialized drug delivery systems.^[2]

Renewable energy

Cobalt boride has also been studied as a catalyst for hydrogen storage and fuel cell technologies.^[3]

Organic synthesis

Cobalt boride is also an effective hydrogenation catalyst used in organic synthesis.^[4] In one study, cobalt boride was found to be the most selective transition metal based catalyst available for the production of primary amines via nitrile reduction, even exceeding other cobalt containing catalysts such as Raney cobalt.^[5]

Preparations

Materials coating

Cobalt boride is produced under high temperature such as 1500 °C. Coatings of cobalt boride on iron are produced by boriding, which involves first introducing a coating of FeB, Fe₂B. On to this iron boride coating is deposited cobalt using a pack cementation process.^[2] Cobalt boride nanoparticles in the size range of 18 to 22 nm have also been produced.^[6]

Catalyst

When used as a catalyst, cobalt boride is prepared by reducing a cobalt salt, such as cobalt(II) nitrate, with sodium borohydride.^[4]^[7] Prior to reduction, the surface area of the catalyst is maximized by supporting the salt on another material; often this material is activated carbon.

References

^ Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida, USA: CRC Press. ISBN 978-1-43982077-3.
^ ^a ^b Yoon, Jin Kook; Man, Jung; Park, Sang Whan (2013). Methods for manufacturing of cobalt boride coating layer on surface of steels by using a pack cementation process. Patent Publication No. US 20130260160 A1.
^ Schlesinger, H. I.; Brown, Herbert C.; Finholt, A. E.; Gilbreath, James R.; Hoekstra, Henry R.; Hyde, Earl K. (January 1953). "Sodium Borohydride, Its Hydrolysis and its Use as a Reducing Agent and in the Generation of Hydrogen". Journal of the American Chemical Society. 75 (1): 215–219. doi:10.1021/ja01097a057.
^ ^a ^b Nishimura, Shigeo (2001). Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis (1st ed.). New York: Wiley-Interscience. pp. 25–26 & 263. ISBN 9780471396987.
^ Barnett, Clive (1969). "Hydrogenation of Aliphatic Nitriles over Transition Metal Borides". Industrial & Engineering Chemistry Product Research and Development. 8 (2): 145–149. doi:10.1021/i360030a009.
^ Kapfenberger, C.; Albert, B.; Pottgen, R.; Huppertz, H. (January 2014). "Synthesis of cobalt boride nanoparticles using RF thermal plasma". Advanced Powder Technology. 25. Advanced Powder Technology Volume 25, Issue 1: 365–371. doi:10.1016/j.apt.2013.06.002.
^ Wu, Chuan; Wu, Feng; Bai, Ying; Yi, Baolian; Zhang, Huamin (2005). "Cobalt boride catalysts for hydrogen generation from alkaline NaBH4 solution". Materials Letters. 59 (14–15): 1748–1751. doi:10.1016/j.matlet.2005.01.058.