Thermoexfoliated graphite as support for production of metal–graphite nanocomposites Original Research Article

The method of chemical deposition of metal salts from water–salt solutions with the subsequent thermal decomposition of salt to metal or metal oxide has been developed for thermoexfoliated graphite (TEG). The type of graphite support and character of metal salt thermal decomposition was shown to influence essentially the dispersity and morphology of metal particles being formed on graphite surface. Preliminary treatment of the initial dispersed graphite by H2SO4 leads to the formation of oxygen-containing groups on its surface, which are the exchange centres fixing the metal cations in graphite–metal (or graphite–metal oxide) composites. Thermal exfoliation of graphite, which is accompanied by the refinement of graphite structure, occurs as a result of oxidized graphite heat treatment. High porosity, defectiveness and chemical activity of TEG surface favour the effective impregnation of TEG by aqueous salt solution. Thermal treatment of the salt-impregnated graphite leads to formation of Co particles on graphite surface. These particles are 70–150 nm in size for TEG–Co at a relatively high metal content (up to 30 wt%) and 200 nm in size for oxidized dispersed graphite–Co at Co content ∼10 wt%.