Two-Step Synthesis of Cobalt Iron Alloy Nanoparticles Embedded in Nitrogen-Doped Carbon Nanosheets/Carbon Nanotubes for the Oxygen Evolution Reaction

Yang Liu; Feng Li; Haidong Yang; Jing Li; Ping Ma; Yan Zhu; Jiantai Ma

doi:10.1002/cssc.201800961

Two-Step Synthesis of Cobalt Iron Alloy Nanoparticles Embedded in Nitrogen-Doped Carbon Nanosheets/Carbon Nanotubes for the Oxygen Evolution Reaction

ChemSusChem. 2018 Jul 20;11(14):2358-2366. doi: 10.1002/cssc.201800961. Epub 2018 Jun 25.

Authors

Yang Liu^{1

2}, Feng Li^{1

2}, Haidong Yang^{1

2}, Jing Li^{1

2}, Ping Ma^{1

2}, Yan Zhu^{1

2}, Jiantai Ma^{1

2}

Affiliations

¹ State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China.
² Gansu Provincial Engineering Laboratory for Chemical Catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, P. R. China.

PMID: 29786972
DOI: 10.1002/cssc.201800961

Abstract

There is a vital need to explore highly efficient and stable non-precious-metal catalysts for the oxygen evolution reaction (OER) to reduce the overpotential and further improve the energy-conversion efficiency. Herein, we report a unique and cost-effective lyophilization and thermal treatment two-step procedure to synthesize a high-performance hybrid consisting of CoFe alloy nanoparticles embedded in N-doped carbon nanosheets interspersed with carbon nanotubes (CoFe-N-CN/CNTs) hybrid. The lyophilization step during the catalyst preparation leads to a uniform dispersion of carbon-like precursors and avoids the agglomeration of metal particles. In addition, the inserted CNTs and doped N in this hybrid provide a good electrical conductivity, an abundance of chemically active sites, good mass transport capability, and effective gas adsorption/release channels. All these lead to a high specific surface area of 240.67 m² g^-1 , favorable stability, and remarkable OER activities with an overpotential of only 285 mV at a current density of 10 mA cm^-2 and a Tafel slope of 51.09 mV dec^-1 in 1.0 m KOH electrolyte, which is even superior to commercial IrO₂ catalysts. The CoFe-N-CN/CNTs hybrid thus exhibits great potential as a highly efficient and earth-abundant anode OER electrocatalyst.

Keywords: alloys; carbon nanotubes; electrochemistry; lyophilization; oxygen evolution reaction.