International Journal of Energy Research, Vol.45, No.4, 6250-6261, 2021
Co-N-doped hierarchically ordered macro/mesoporous carbon as bifunctional electrocatalyst toward oxygen reduction/evolution reactions
Exploring progressed activity and stability, electrocatalyst toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), has been the most considerable factor in extensive commercialization of metal-air batteries and fuel cells. Herein, Co/N co-doped 3D hierarchical porous bifunctional oxygen electrocatalyst was synthesized using F127 as soft template and PMMA nanosphere as hard template to build hierarchically ordered macro/mesoporous porous nanostructure. The as-obtained macro/mesoporous Co-N-doped carbon endowing its 3D ordered hierarchical porosity and satisfactory surface area, leading to superior performance for ORR, OER, and rechargeable Zn-air battery. For ORR, the catalyst showed superior ORR activity with an attractive half-wave potential of 0.85 V (vs RHE), remarkable methanol tolerance, and robust long-term stability under alkaline electrolyte. For OER, the as-synthetized electrocatalyst exhibited low overpotential of 1.67 V (vs RHE) under the current density of 10 mA/cm(2). Moreover, the Zn-air battery assembled from the hierarchical porous catalyst displayed a high peak power density of 146 mW/cm(2).