Nanotechnology

Electrode

Organic chemistry

Composite number

Nuclear chemistry

Engineering

Catalysis

Carbon fibers

Physical chemistry

Nanoparticle

Copolymer

Composite material

Inorganic chemistry

Chemistry

Metallurgy

Materials science

Ethylene glycol

Styrene

Carbide

Electrolyte

Chemical engineering

Cobalt

Polymer

Nitrogen

Oxygen

Mesoporous material

Advanced Science

Sub‐50 nm iron–nitrogen‐doped hollow carbon sphere‐encapsulated iron carbide nanoparticles (Fe 3 C‐Fe,N/C) are synthesized by using a triblock copolymer of poly(styrene‐ b ‐2‐vinylpyridine‐ b ‐ethylene oxide) as a soft template. Their typical features, including a large surface area (879.5 m 2 g −1 ), small hollow size (≈16 nm), and nitrogen‐doped mesoporous carbon shell, and encapsulated Fe 3 C nanoparticles generate a highly active oxygen reduction reaction (ORR) performance. Fe 3 C‐Fe,N/C hollow spheres exhibit an ORR performance comparable to that of commercially available 20 wt% Pt/C in alkaline electrolyte, with a similar half‐wave potential, an electron transfer number close to 4, and lower H 2 O 2 yield of less than 5%. It also shows noticeable ORR catalytic activity under acidic conditions, with a high half‐wave potential of 0.714 V, which is only 59 mV lower than that of 20 wt% Pt/C. Moreover, Fe 3 C‐Fe,N/C has remarkable long‐term durability and tolerance to methanol poisoning, exceeding Pt/C regardless of the electrolyte.

Sub‐50 nm Iron–Nitrogen‐Doped Hollow Carbon Sphere‐Encapsulated Iron Carbide Nanoparticles as Efficient Oxygen Reduction Catalysts