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.