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Zinc‐Mediated Template Synthesis of Fe‐N‐C Electrocatalysts with Densely Accessible Fe‐N x Active Sites for Efficient Oxygen Reduction
Author(s) -
Chen Guangbo,
Liu Pan,
Liao Zhongquan,
Sun Fanfei,
He Yanghua,
Zhong Haixia,
Zhang Tao,
Zschech Ehrenfried,
Chen Mingwei,
Wu Gang,
Zhang Jian,
Feng Xinliang
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201907399
Subject(s) - materials science , zinc , catalysis , noble metal , aqueous solution , nanoparticle , metal , electrochemistry , reversible hydrogen electrode , chemical engineering , inorganic chemistry , nanotechnology , electrode , chemistry , metallurgy , working electrode , organic chemistry , engineering
Owing to their earth abundance, high atom utilization, and excellent activity, single iron atoms dispersed on nitrogen‐doped carbons (Fe‐N‐C) have emerged as appealing alternatives to noble‐metal platinum (Pt) for catalyzing the oxygen reduction reaction (ORR). However, the ORR activity of current Fe‐N‐C is seriously limited by the low density and inferior exposure of active Fe‐N x species. Here, a novel zinc‐mediated template synthesis strategy is demonstrated for constructing densely exposed Fe‐N x moieties on hierarchically porous carbon (SA‐Fe‐NHPC). During the thermal treatment of 2,6‐diaminopyridine/ZnFe/SiO 2 complex, the zinc prevents the formation of iron carbide nanoparticles and the SiO 2 template promotes the generation of hierarchically pores for substantially improving the accessibility of Fe‐N x moieties after subsequent leaching. As a result, the SA‐Fe‐NHPC electrocatalysts exhibit an unprecedentedly high ORR activity with a half‐wave potential ( E 1/2 ) of 0.93 V in a 0.1 m KOH aqueous solution, which outperforms those for Pt/C catalyst and state‐of‐the‐art noble metal‐free electrocatalysts. As the air electrode in zinc–air batteries, the SA‐Fe‐NHPC demonstrates a large peak power density of 266.4 mW cm −2 and superior long‐term stability. Therefore, the developed zinc‐mediated template synthesis strategy for boosting the density and accessibility of Fe‐N x species paves a new avenue toward high‐performance ORR electrocatalysts.