Oxidation with Simon's reagent and HNO₃/H₂SO₄ of turbostratic graphitic carbon prepared catalytically by nickel particles (20nm) in a carbonized resin

Abstract

Four carbons, of heat treatment temperature 2800° C, were prepared from pure phenol formaldehyde resin (A-component), from this resin doped with nickel acetylacetonate (T_s-component), from a coal-tar pitch (T_p-component) and from the resin containing 30 wt% nickel particles (50 μm) (G-component). These carbons are characterized by X-ray diffraction (d ₀₀₂ and L _c), high-resolution phase-contrast electron microscopy, Raman spectroscopy and oxidation with Simon's reagent and mixed acid HNO₃/H₂SO₄. The X-ray diffraction patterns show that graphitization increased A<T_s⩽T_p<G. The Raman spectra, using the ratio R=I (1355 cm⁻¹)/I(1575 cm⁻¹) indicate that the T_s-component has the least number of imperfections in the lattice. The T_s- and G-components react faster than other carbons in Simon's reagent but react slower in mixed acids. These faster rates are associated with lower activation energies. The Simon's reagent reacts preferentially with the more graphitic structures of the G-component unlike the T_s-component which appears to be structurally homogeneous. Rates of oxidation with mixed acid increase G<T_p<T_s<A.