Graphene-Supported Silver-Iron Carbon Nitride Derived from Thermal Decomposition of Silver Hexacyanoferrate as Effective Electrocatalyst for the Oxygen Reduction Reaction in Alkaline Media

Silver-iron carbon nitride has been obtained by pyrolysis (under inert atmosphere) of silver hexacyanoferrate(II), precipitated on graphene nanoplatelets, and examined as electrocatalyst for oxygen reduction reaction in alkaline media in comparison to silver nanoparticles and iron carbon nitride (prepared separately in a similar manner on graphene nanoplatelets). The catalytic materials have been studied in 0.1 M potassium hydroxide electrolyte using such electrochemical diagnostic techniques as cyclic voltammetry and rotating ring-disk electrode voltammetry. Upon application of graphene nanoplateletssupported mixed silver-iron carbon nitride catalyst, the reduction of oxygen proceeds at more positive potentials and the amounts of hydrogen peroxide (generated during reduction of oxygen at potentials more positive than 0.3 V) are lower relative to silver nanoparticles and iron carbon nitride (supported on graphene nanoplatelets) examined separately. Promoting effect is ascribed to high activity of silver toward the reduction/decomposition of H2O2 in basic medium. Additionally, it has been observed that the systems based on carbon nitrides show considerable stability due to strong fixation of metal complexes to CN shells.