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–Nx, and the high intrinsic activity of the Co–Nx 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.