Atomic Co–N4 and Co nanoparticles confined in COF@ZIF-67 derived core–shell carbon frameworks: bifunctional non-precious metal catalysts toward the ORR and HER

The core–shell structured carbon frameworks, containing uniform Co nanoparticles and atomic CoN 4 sites, were synthesized from TP-BPY-COF@ZIF-67 for the first time, which enable catalyzing the ORR and HER with high activities.