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Nitrogen‐Doped Nanoporous Carbon/Graphene Nano‐Sandwiches: Synthesis and Application for Efficient Oxygen Reduction
Author(s) -
Wei Jing,
Hu Yaoxin,
Liang Yan,
Kong Biao,
Zhang Jin,
Song Jingchao,
Bao Qiaoliang,
Simon George P.,
Jiang San Ping,
Wang Huanting
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502311
Subject(s) - materials science , graphene , nanoporous , oxide , chemical engineering , carbon fibers , carbonization , electrocatalyst , nanotechnology , inorganic chemistry , electrode , electrochemistry , composite material , composite number , scanning electron microscope , chemistry , metallurgy , engineering
A zeolitic‐imidazolate‐framework (ZIF) nanocrystal layer‐protected carbonization route is developed to prepare N‐doped nanoporous carbon/graphene nano‐sandwiches. The ZIF/graphene oxide/ZIF sandwich‐like structure with ultrasmall ZIF nanocrystals (i.e., ≈20 nm) fully covering the graphene oxide (GO) is prepared via a homogenous nucleation followed by a uniform deposition and confined growth process. The uniform coating of ZIF nanocrystals on the GO layer can effectively inhibit the agglomeration of GO during high‐temperature treatment (800 °C). After carbonization and acid etching, N‐doped nanoporous carbon/graphene nanosheets are formed, with a high specific surface area (1170 m 2 g −1 ). These N‐doped nanoporous carbon/graphene nanosheets are used as the nonprecious metal electrocatalysts for oxygen reduction and exhibit a high onset potential (0.92 V vs reversible hydrogen electrode; RHE) and a large limiting current density (5.2 mA cm −2 at 0.60 V). To further increase the oxygen reduction performance, nanoporous Co‐N x /carbon nanosheets are also prepared by using cobalt nitrate and zinc nitrate as cometal sources, which reveal higher onset potential (0.96 V) than both commercial Pt/C (0.94 V) and N‐doped nanoporous carbon/graphene nanosheets. Such nanoporous Co‐N x /carbon nanosheets also exhibit good performance such as high activity, stability, and methanol tolerance in acidic media.