Single Cobalt Atom and N Codoped Carbon Nanofibers as Highly Durable Electrocatalyst for Oxygen Reduction Reaction

Transition-metal and nitrogen-codoped carbon-based (TM-N/C) catalysts are promising candidates for catalyzing the oxygen reduction reaction (ORR). However, TM-N/C catalysts suffer from insufficient ORR activity, unclear active site structure, and poor durability, particularly in acidic solution. Herein, we report single Co atom and N codoped carbon nanofibers (Co–N/CNFs) catalyst with high durability and desirable ORR activity in both acidic and alkaline solutions. The half-wave potential of the ORR shows a negligible decrease after a 10 000-cycle accelerated durability test. The high ORR durability is originated from the structural stability of the atomically dispersed Co-based active site, as revealed by probing analysis and density functional theory calculations. A passive direct methanol fuel cell with the Co–N/CNFs cathode delivers a maximal power density of 16 mW cm–2 and a remarkable stability during a 200 h test, demonstrating the application potential of Co–N/CNFs. The breakthrough of the highly durable TM-N/C ORR catalyst could open an avenue for affordable and durable fuel cells.