From Supramolecular Species to Self-Templated Porous Carbon and Metal-Doped Carbon for Oxygen Reduction Reaction Catalysts.

The preparation of carbon materials usually involves the decomposition of precursors and the reorganization of the as-generated fragments. However, the cleavage of bonds and the simultaneous formation of new bonds at nearly the same positions prevents effective yet precise fabrication. Herein, a supramolecular precursor, cucurbit[6]uril, that contains multiple bonds with distinct bond strengths is proposed to decouple the twin problem of simultaneous bond cleavage and formation, allowing multistage transformations to hierarchical porous carbon and metal-doped carbon in a single yet effective pyrolysis step without the need of a template or additional purification. As a proof-of-concept, the Fe-doped carbon electrocatalysts realized a Pt/C-like half-wave potential of 0.869 V vs. RHE and small Tafel slope of 51.3 mV dec-1 in oxygen reduction reaction.