High-performance atomic Co/N co–doped porous carbon catalysts derived from Co–doped metal–organic frameworks for oxygen reduction

Improving the activity and durability of carbon-based catalysts is a key challenge for their application in fuel cells. Herein, we report a highly active and durable Co/N co-doped carbon (Co N C) catalyst prepared via pyrolysis of Co–doped zeolitic–imidazolate framework–8 (ZIF–8), which was synthesized by controlling the feeding sequence to enable Co to replace Zn in the metal–organic framework (MOF). The catalyst exhibited excellent oxygen reduction reaction (ORR) performance, while the half-wave potential decreased by only 8 mV after 5,000 accelerated stress test (AST) cycles in an acidic solution. Furthermore, the catalyst exhibited satisfactory cathodic catalytic performance when utilized in a hydrogen/oxygen single proton exchange membrane (PEM) fuel cell and a Zn-air battery, yielding maximum power densities of 530 and 164 mW cm −2 , respectively. X-ray absorption spectroscopy (XAS) and high-angle annular dark field-scanning transmission electron microscopy (HAAD–STEM) analyses revealed that Co was present in the catalyst as single atoms coordinated with N to form Co–N moieties, which results in the high catalytic performance. These results show that the reported catalyst is a promising material for inclusion into future fuel cell designs.