Honeycomb-like Self-Supported Co-N-C Catalysts with an Ultrastable Structure: Highly Efficient Electrocatalysts toward Oxygen Reduction Reaction in Alkaline and Acidic Solutions

Because of their outstanding electrocatalytic activity, M-N-C catalysts have got increasing attention, especially for oxygen reduction reaction (ORR). Nevertheless, M-N-C catalysts still face the great challenges of long-term stability and mass production for practical applications. In this work, we reported the synthesis and study of a honeycomb-like self-supported Co-N-C catalyst, which exhibited desirable activity and excellent stability for ORR in both alkaline and acidic mediums. Specifically, after a 10,000-cycle accelerated durability test, Co -N-C-700 showed a slight decrease of 5 mV in alkaline and no attenuation in acidic solutions for the half-wave potential. The unprecedented ORR performance of the self-supported Co-N-C may be contributed to the unique honeycomb-like morphology, high active surface area, high contents of graphitic N and Co-N-x and the high intrinsic activity of the Co-N-x moiety. The breakthrough of the highly durable and scalable fabrication of M-N-C catalysts could open a promising way for their potential applications in many fields, including fuel cells and metal-air batteries.