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Co Nanoparticles Confined in 3D Nitrogen‐Doped Porous Carbon Foams as Bifunctional Electrocatalysts for Long‐Life Rechargeable Zn–Air Batteries
Author(s) -
Jiang Hao,
Liu Yong,
Li Wenzhang,
Li Jie
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201703739
Subject(s) - bifunctional , carbonization , materials science , catalysis , chemical engineering , oxygen evolution , nanoparticle , electrocatalyst , bifunctional catalyst , carbon fibers , cobalt , inorganic chemistry , nanotechnology , electrode , chemistry , electrochemistry , organic chemistry , composite material , metallurgy , scanning electron microscope , composite number , engineering
Proper design and simple preparation of nonnoble bifunctional electrocatalysts with high cost performance and strong durability for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is highly demanded but still full of enormous challenges. In this work, a spontaneous gas‐foaming strategy is presented to synthesize cobalt nanoparticles confined in 3D nitrogen‐doped porous carbon foams (CoNCF) by simply carbonizing the mixture of citric acid, NH 4 Cl, and Co(NO 3 ) 2 ·6H 2 O. Thanks to its particular 3D porous foam architecture, ultrahigh specific surface area (1641 m 2 g −1 ), and homogeneous distribution of active sites (C–N, Co–N x , and Co–O moieties), the optimized CoNCF‐1000‐80 (carbonized at 1000 °C, containing 80 mg Co(NO 3 ) 2 ·6H 2 O in precursors) catalyst exhibits a remarkable bifunctional activity and long‐term durability toward both ORR and OER. Its bifunctional activity parameter (Δ E ) is as low as 0.84 V, which is much smaller than that of noble metal catalyst and comparable to state‐of‐the‐art bifunctional catalysts. When worked as an air electrode catalyst in rechargeable Zn–air batteries, a high energy density (797 Wh kg −1 ), a low charge/discharge voltage gap (0.75 V), and a long‐term cycle stability (over 166 h) are achieved at 10 mA cm −2 .