Electrocatalytic Activity of Nanocomposites of Sulphur Doped Graphene Oxide and Nanosized Cobalt Phthalocyanines

In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X-ray photon spectroscopy, X-ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPcNP). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPcNP-rSDGONS at 1.49 mu M. The same electrode gave a high adsorption equilibrium constant of 1.27 x 10(3) mol(-1) and a Gibbs free energy of -17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface.