Abundant Co-Nx sites onto hollow MOF-Derived nitrogen-doped carbon materials for enhanced oxygen reduction.

It is of great importance to find non-precious metal based oxygen reduction reaction (ORR) catalysts with high stability, high performance and low cost. In this context, hierarchically porous carbon-based nanomaterials doped with heteroatoms are regarded as one of promising catalysts for ORR. Herein, a bottom-up approach is proposed by using the initial MOF-derived CoO@ZIF-67 core-shell structure as a template to obtain hollow cobalt-anchored N-doped carbon material followed by acid etching (A-CoNC). It exhibits a type of hollow porous nitrogen-carbon network anchored by well-dispersed atomic Co-N x sites with high activity and stable catalytic performance. The as-obtained A-CoNC shows high electrocatalytic ORR activity, good reaction selectivity with the low Tafel slope of 55.5 mV dec−1, large limited current density of 5.37 mA cm−2 and excellent long-term stability (retention = 96.1%, time = 10 h). Furthermore, A-CoNC can also be serving as efficient electrocatalysts for zinc-air battery with a high power density of 144.0 mW cm−2. Our synthetic strategy from the MOF-derived core-shell structure to ORR electrocatalyst provides new pathway for the design and preparation of highly efficient electro-/photo-catalysts stemmed from MOFs materials. [Display omitted] • A bottom-up method is proposed to prepare hollow porous Co,N-doped carbon materials. • The obtained MOF-derived core-shell structure is endowed with decent surface area. • The nitrogen-carbon network anchored by rich dispersed Co-N x sites is obtained. • The Co,N-doped carbon materials show an excellent ORR activity for Zn-air battery. [ABSTRACT FROM AUTHOR]