This paper describes the electrochemical performance of carbon onions as electrode materials in electrical double layer capacitors with water electrolytes. Onion‐like carbon (OLC) species were produced by vacuum annealing of detonation nanodiamonds (NDs) powder at 1170–2170 K. The material capability of the charge accumulation in the electric double layer was estimated using the voltammetric technique. The correlations between specific capacitance, surface area and conductivity were found. Charge‐discharge measurements revealed a dependence of the specific capacitance of OLC on the degree of diamond particle graphitization and defectness of particle surfaces. Promising capacitance values, ranging within 20−40 F g–1 and within 70−100 F g–1 were found for the OLC materials operating respectively in acid electrolytic solution (1 M H2SO4) and alkaline electrolytic solution (6 M KOH). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Development of graphene spintronic devices relies on transforming it into a material with a spin order. Attempts to make graphene magnetic by introducing zigzag edge states have failed due to energetically unstable structure of torn zigzag edges. Here, we report on the formation of nanoridges, i.e., stable crystallographically oriented fluorine monoatomic chains, and provide experimental evidence for strongly coupled magnetic states at the graphene-fluorographene interfaces. From the first principle calculations, the spins at the localized edge states are ferromagnetically ordered within each of the zigzag interface whereas the spin interaction across a nanoridge is antiferromagnetic. Magnetic susceptibility data agree with this physical picture and exhibit behaviour typical of quantum spin-ladder system with ferromagnetic legs and antiferromagnetic rungs. The exchange coupling constant along the rungs is measured to be 450 K. The coupling is strong enough to consider graphene with fluorine nanoridges as a candidate for a room temperature spintronics material.

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A simple method for formation of CdS nanoparticles on the surface of carbon nanotubes (CNTs) aligned perpendicularly to the silicon substrate has been developed. The size and shape of the CdS nanoparticles were found to depend on the temperature of a solution containing CdCl(2), (NH(2))(2)CS, and NH(3) and the deposition time. Electron microscopy study revealed a direct contact between CdS nanoparticles and CNT surface. X-Ray photoelectron spectroscopy examination of the CdS/CNT hybrid material detected surface oxidation of the grown nanoparticles.