Size Control of Nanographene Supported Iron Oxide Nanoparticles Enhances Their Electrocatalytic Performance for the Oxygen Reduction and Oxygen Evolution Reactions

Reduced carbon layers, differing in lateral dimension, are exploited as reduction agents for iron(II) salts, resulting in the decoration of the carbon framework by iron oxide nanoparticles. Depending on the choice of the carbon starting material, the average size of the formed nanoparticles is situated between 3 and 50 nm. Those composite materials, free of stabilization or capping agents, show remarkable catalytic activity in the oxygen reduction reaction (ORR) and in the oxygen evolution reaction (OER). The electrochemical performance, the activity, and the selectivity depends dramatically on the respective size of the nanoparticles generated.