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Graphene‐Encapsulated Co 9 S 8 Nanoparticles on N,S‐Codoped Carbon Nanotubes: An Efficient Bifunctional Oxygen Electrocatalyst
Author(s) -
Jia Nan,
Liu Jing,
Gao Yunshan,
Chen Pei,
Chen Xinbing,
An Zhongwei,
Li Xifei,
Chen Yu
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201900383
Subject(s) - electrocatalyst , bifunctional , nanoparticle , carbon nanotube , graphene , carbon fibers , oxygen evolution , materials science , nanotechnology , oxygen reduction reaction , oxygen , catalysis , chemistry , chemical engineering , inorganic chemistry , electrochemistry , electrode , organic chemistry , composite number , composite material , engineering
An inexpensive and efficient bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is central to the rechargeable zinc–air battery. Herein, a nanohybrid, in which N,S‐codoped carbon nanotubes were decorated with Co 9 S 8 nanoparticles encapsulated in porous graphene layers, was fabricated by a one‐step heat‐treatment process. The N,S dopant species were the major active sites for the ORR, and Co 9 S 8 nanoparticles were mainly responsible for the OER. Compared with commercial 20 wt % Pt/C and Ir/C electrocatalysts, this nanohybrid exhibited a comparable ORR half‐wave potential (0.831 V vs. reversible hydrogen electrode) and OER potential (1.591 V at 10 mA cm −2 ), better long‐term stability in an alkaline medium, and a narrower potential gap (0.76 V) between ORR and OER. Furthermore, as air electrode of the rechargeable zinc–air battery, it delivered a low charge–discharge voltage gap (0.65 V at 5 mA cm −2 ), high open‐circuit potential (1.539 V), good specific capacity (805 mA h g - 1Znat 5 mA cm −2 ), and excellent cycling stability (48 h), superior to those of commercial Pt/C and Ir/C catalysts, and thus showed promise for applications in renewable energy conversion devices.