Dual-Shelled Multidoped Hollow Carbon Nanocages with Hierarchical Porosity for High-Performance Oxygen Reduction Reaction in Both Alkaline and Acidic Media.

The rational design and facile synthesis of metal organic framework (MOF)-derived carbon materials with high oxygen reduction reaction (ORR) activity still remains challenging. Herein, we report on a simple yet robust route to dual-shelled Co, N, and S co-doped hollow carbon nanocages (denoted Co-N/S-DSHCN) with outstanding ORR performance. The concurrent compositional and structural engineering of the zeolitic imidazolate framework (ZIF-67), enabled by its coating with trithiocyanuric acid (TCA), yields core-shelled precursor particles which are subsequently carbonized into Co-N/S-DSHCN. Notably, Co-N/S-DSHCN-3.5 outperforms the commercial Pt/C, representing a +25 mV onset potential (Eon) and a +43 mV half-wave potential (E1/2) in 0.1 M KOH and a comparable E1/2 to Pt/C in 0.5 M H2SO4, respectively. Such impressive ORR activities of Co-N/S-DSHCN-3.5 originate from the effective synergy of Co, N, and S co-doping (i.e., a compositional tuning) in conjunction with a unique dual-shelled hollow architecture containing hierarchical porosity (i.e., a structural tailoring).