Cobalt and nitrogen-codoped ordered mesoporous carbon as highly efficient bifunctional catalysts for oxygen reduction and hydrogen evolution reactions

Abstract

The high cost and limited reserves of noble metals such as Pt have hampered their large-scale commercial applications in the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Herein, we developed a simple silica template approach to form porous carbons codoped with nitrogen and cobalt as highly efficient bifunctional electrocatalysts for the ORR and HER. The resulting porous carbons exhibited excellent electrocatalytic activity for the ORR in alkaline media, which compares favorably with that of commercial Pt/C (20 wt%), and had superior durability and excellent methanol tolerance. The porous carbons also showed superior performance for the HER, with a low onset potential of −0.04 V, a Tafel slope of 49 mV dec⁻¹, an overpotential of −0.106 V at a current density of 10 mA cm⁻², and remarkable durability. These results demonstrate that the Co, N-doped carbons are promising bifunctional catalysts for fuel cell applications.