A doping-adsorption-pyrolysis strategy for constructing atomically dispersed cobalt sites anchored on a N-doped carbon framework as an efficient bifunctional electrocatalyst for hydrogen evolution and oxygen reduction

Renewable energy technology development focuses on the exploration of economical and efficient non-precious metal catalysts to replace precious metal catalysts in electrocatalytic reactions including oxygen reduction (ORR) and hydrogen evolution (HER). Herein, we synthesized a cobalt single atom catalyst anchored on a N-doped carbon framework by a doping-adsorption-pyrolysis strategy. The optimized Co SAs/CN-3 catalyst showed excellent HER and ORR bifunctional electrocatalytic performance, which could be attributed to the highly dispersed Co-N₄ active sites, large specific surface area and abundant pore structure. Density functional theory shows that the isolated active Co-N₄ site shows low hydrogen adsorption Gibbs free energy, and promotes the adsorption of H and oxygen-containing intermediates in HER and ORR. This work not only provides a new idea for the construction of transition metal catalysts with atomic accuracy but also provides powerful guidance for the development of efficient bifunctional electrocatalysts.