Scalable nitrogen-enriched porous sub-100 nm graphitic carbon nanocapsules for efficient oxygen reduction reaction in different media

The oxygen reduction reaction (ORR) is deemed a sustainable energy source; however, developing green, earth-abundant, and efficient noble-metal-free catalysts for efficient ORR in different media remains a grand challenge. Herein, we present a scalable, facile, environmentally benign, and one-pot strategy for the fabrication of eco-friendly nitrogen-enriched graphitic-like hierarchical porous sub-100 nm carbon (denoted as N-HMPC) nanocapsules with controllable N-content for ORR. The synthesis route is based on in situ organic-organic self-assembly of Pluronic F127 copolymer micelles and resorcinol-melamine-formaldehyde in the presence of a silica template followed by carbonization and eroding the silica core. The as-formed N-HMPC nanocapsules have a core-shell morphology (& SIM;84 nm), hierarchical porosity, high surface area of (790 m(2) g(-1)), and tunable nitrogen content (9-25%). Intriguingly, N-HMPC nanocapsules exhibit an analogous ORR activity to the commercial Pt/C catalyst (20% Pt) in the alkaline and acidic electrolytes, besides superior durability and inimitable tolerance to methanol and CO poisonings due to the hollow core-shell architecture and abundant nitrogen. A judicious combination of experimental and density functional theory (DFT) simulations delineated the ORR pathway and mechanism for N-HMPC in acidic and alkaline electrolytes. The presented approach may open new avenues for the rational design of metal-free green electrocatalysts for ORR.

Automated summary

A scalable, facile, and environmentally benign strategy was developed for the fabrication of metal-free nitrogen-enriched graphitic-like porous carbon nanocapsules for efficient oxygen reduction reaction (ORR). The nitrogen-enriched nanocapsules exhibited comparable ORR activity to commercial Pt/C catalyst in both alkaline and acidic electrolytes, with superior durability and tolerance to methanol and CO poisonings. This approach may provide new opportunities for the rational design of green electrocatalysts for ORR.