A graphene-directed assembly route to hierarchically porous Co-Nx/C catalysts for high performance oxygen reduction

Jing Wei, Yaoxin Hu, Zhangxiong Wu, Yan Liang, Sookwan Leong, Biao Kong, Xinyi Zhang, Dongyuan Zhao, George P. Simon, Huanting Wang

Research output: Contribution to journalArticleResearchpeer-review

119 Citations (Scopus)

Abstract

The development of non-precious metal catalysts for efficient oxygen reduction is of significance for many advanced electrochemical devices such as fuel cells and metal-air batteries. Herein, we develop a graphene-directed assembly route to synthesize hierarchically nanoporous Co-Nx/C materials with a macro/meso/microporous structure, high specific surface area (i.e. 512 m2 g-1) and excellent conductivity using graphene oxide (GO) supported zeolitic imidazolate framework nanocrystal arrays as a catalyst precursor, followed by the carbonization and acid leaching process. In this route, GO acts as a structure-directing agent to construct ZIF nanocrystal arrays supported on GO nanosheets. During the carbonization process, the resulting reduced graphene oxide functions as a binder and electrical conductor to connect individual ZIF-derived carbon nanoparticles into the macroporous structure and increase the overall conductivity. ZIF nanocrystals themselves are also converted into meso/microporous carbon nanoparticles without using any other template. The hierarchically porous Co-Nx/C materials exhibit high ORR catalytic activity, superior stability and good methanol tolerance under both alkaline and acidic conditions.
Original languageEnglish
Pages (from-to)16867 - 16873
Number of pages7
JournalJournal of Materials Chemistry A
Volume3
Issue number32
DOIs
Publication statusPublished - 2015

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