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arXiv · 1509.00575

The characterization of Co-nanoparticles supported on graphene

P. Bazylewski·D. W. Boukhvalov·A. I. Kukharenko·E. Z. Kurmaev·A. Hunt·A. Moewes·Y. H. Lee·S. O. Cholakh·G. S. Chang
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Abstract

The results of density functional theory calculations and measurements using X-ray photoelectron spectroscopy of Co-nanoparticles dispersed on graphene/Cu are presented. It is found that for low cobalt thickness (0.02 nm - 0.06 nm) the Co forms islands distributed non-homogeneously which are strongly oxidized under exposure to air to form cobalt oxides. At greater thicknesses up to 2 nm the upper Co-layers are similarly oxidized whereas the lower layers contacting the graphene remain metallic. The measurements indicate a Co2+ oxidation state with no evidence of a 3+ state appearing at any Co thickness, consistent with CoO and Co[OH]2. The results show that thicker Co (2nm) coverage induces the formation of a protective oxide layer while providing the magnetic properties of Co nanoparticles.

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P. Bazylewski, D. W. Boukhvalov, A. I. Kukharenko, E. Z. Kurmaev, A. Hunt, A. Moewes, Y. H. Lee, S. O. Cholakh, G. S. Chang. 2015-09-02. The characterization of Co-nanoparticles supported on graphene. https://arxiv.org/abs/1509.00575

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