Facile Synthesis of Mesoporous α-FeO@g-CN-NCs for Efficient Bifunctional Electro-catalytic Activity (OER/ORR).

Mesoporous α-iron oxide@graphitized-carbon nitride nanocomposites (α-FeO@g-CN-NCs) were synthesized using urea-formaldehyde (UF) resins at 400 °C/2 h. The mesoporous nature of the prepared nanocomposites was observed from electron microscopy and surface area measurements. The electrochemical measurements show the bifunctional nature of mesoporous α-FeO@g-CN-NCs in electrolysis of water for oxygen evolution and oxygen reduction reactions (OER/ORR) using 0.5 M KOH. Higher current density of mesoporous α-FeO@g-CN-NCs reveals the enhanced electrochemical performance compared to pure FeO nanoparticles (NPs). The onset potential, over-potential and Tafel slopes of mesoporous α-FeO@g-CN-NCs were found lower than that of pure α-FeO-NPs. Rotating disc electrode experiments followed by the K-L equation were used to investigate 4e redox system. Therefore, the mesoporous α-FeO@g-CN-NCs bifunctional electro-catalysts can be considered as potential future low-cost alternatives for Pt/C catalysts, which are currently used in fuel cells.