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Fe/Fe 3 C Nanoparticles Encapsulated in N‐Doped Hollow Carbon Spheres as Efficient Electrocatalysts for the Oxygen Reduction Reaction over a Wide pH Range
Author(s) -
Liu Yanhui,
Wang Xingkun,
Zhao Bolin,
Shao Xin,
Huang Minghua
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201806111
Subject(s) - catalysis , proton exchange membrane fuel cell , methanol , mesoporous material , carbon fibers , electrolysis , nanoparticle , materials science , chemical engineering , yield (engineering) , chemistry , inorganic chemistry , electrocatalyst , electrochemistry , nanotechnology , electrode , electrolyte , organic chemistry , metallurgy , composite material , composite number , engineering
Nonprecious‐metal‐based electrocatalysts with low cost, high activity, and stability are considered as one of the most promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR). Herein, an economical and easy‐to‐fabricate catalyst is developed, that is, Fe/Fe 3 C embedded in N‐doped hollow carbon spheres (Fe/Fe 3 C/NHCS), which gave the half‐wave potential of 0.84 V in 0.1 m KOH, similar to the commercial Pt/C catalyst. Surprisingly, the favorable ORR performance of the as‐prepared catalyst was obtained in both acidic and neutral conditions with almost a four‐electron pathway and low H 2 O 2 yield, which desirable the development of the proton exchange membrane (PEM) and microbial electrolysis cell (MEC) technology. Additionally, the obtained catalyst demonstrated better long‐term stability and high methanol tolerance over a wide range of pH. These features could be mainly attributed to the synergistic effect between Fe/Fe 3 C and Fe‐N x sites, the hollow structure with mesopores, and the well‐dispersed Fe/Fe 3 C nanoparticles owing to the existence of the abundant hydrophilic groups within the HCS precursor. As such, designing an efficient and cheap ORR catalyst that can operate at alkaline, acidic, and neutral solutions is highly desirable, yet challenging.