Reduced graphene oxide supported nitrogen-doped porous carbon-coated NiFe alloy composite with excellent electrocatalytic activity for oxygen evolution reaction

doi:10.1016/j.apsusc.2019.07.083

Applied Surface Science

Volume 493, 1 November 2019, Pages 963-974

https://doi.org/10.1016/j.apsusc.2019.07.083 Get rights and content

Highlights

•
Graphene supported N-doped carbon-coated NiFe alloy was prepared by a facile pyrolysis route.
•
The NiFe@NC/RGO exhibits excellent electrocatalytic activity for oxygen evolution reaction.
•
It delivers an overpotential of 223 mV at 10 mA cm⁻² with a Tafel slope of 48.7 mV dec⁻¹ in 1 M KOH.
•
It outperforms commercial noble metal-based catalyst of RuO₂ and most catalysts reported so far.
•
The outstanding OER activity is ascribed to the core-shell structure and the introduction of RGO.

Abstract

Designing of cost-effective electrocatalysts for efficient oxygen evolution reaction (OER) is highly desired for the practical production of clean hydrogen energy. Herein, reduced graphene oxide (RGO) supported N-doped porous carbon-coated NiFe alloy composite (NiFe@NC/RGO) was synthesized via a facile pyrolysis route. The introduction of RGO effectively protects the active NiFe component from agglomeration and largely promotes charge transfer. Meanwhile, the formation of porous N-doped carbon shell provides sufficient contact between active species and electrolyte, thus exposing plenty of accessible active sites. Specifically, the optimized NiFe@NC/RGO composite shows superior electrocatalytic performance, delivering an overpotential as low as 223 mV at current density of 10 mA cm⁻², and a small Tafel slope of 48.7 mV dec⁻¹ in 1 M KOH solution, which outperforms commercial precious metal oxide catalysts such as RuO₂ and a vast majority of electrocatalysts reported so far. Long-term cycling test demonstrates that the overpotential at current density of 10 mA cm⁻² has almost no change after 1000 cycles at a scan rate of 50 mV s⁻¹, indicating its quite good stability. The low-cost and high-performance electrocatalyst developed in this work shows great potential for practical hydrogen production from electrolysis of water.

Graphical abstract

Introduction

The growing energy crisis induced by constant consumption of fossil fuels urges us to develop new energy sources to replace traditional fossil fuels. Water splitting is considered as a promising approach to produce clean hydrogen energy [1,2], which involves two half-cell reactions: hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The key issue for hydrogen production from water electrolysis is the design of low-cost and high-efficient electrocatalysts to address the sluggish reaction kinetics and to replace the traditional noble metal-based catalysts with earth-abundant materials [[3], [4], [5]].

To date, a variety of non-precious materials have been extensively investigated as OER catalysts. Substantial transition metal-based catalysts, especially Fe, Co, and Ni-based catalysts, have gained cumulative concerns inspired by their high theoretical activity, low cost and abundant reserves [6,7]. Though considerable Fe, Co, and Ni-based materials such as metal alloy [8], metal hydroxides [9], metal sulfide or selenide [[10], [11], [12]], and metal phosphide or phosphates [[13], [14], [15], [16]] have been successfully exploited and used in OER or water splitting reaction, these materials usually afford high overpotentials of 0.35–0.45 V in 1 M KOH [17] and meanwhile, they often encounter some problems such as severe particle agglomeration and easy corrosion due to the leaching of anions such as S and P during the long-term catalytic process [18,19]. Therefore, it is desired to further improve the Co, Fe and Ni-based OER electrocatalysts for practical water electrolysis [20]. Currently, combining these catalysts with carbonaceous materials to construct carbon-encapsulated composites has been proved to be an effective way to improve their electrocatalytic performance [21]. Among various strategies for achieving carbon-encapsulated structures, metal organic frameworks (MOFs) precursor route is highly efficient due to the organic-inorganic hybrid structure and high porosity of metal organic frameworks [22,23]. Moreover, with nitrogen-rich MOFs as precursors, N-doped carbon encapsulated nanomaterials can be easily obtained, which are beneficial to further enhance the catalytic activity owing to the lower work function of N-doped carbon [[24], [25], [26], [27], [28]]. In addition, it was reported that the introduction of Fe can synergize with Ni or Co to promote OER catalytic activity. For instance, Corrigan et al. [29] reported that Ni-based materials exhibit significantly improved catalytic activity after the introduction of Fe. Similarly, Cai et al. [30] reported that CoFe bimetal/N-doped carbon nanotube composite exhibits good catalytic activity for OER due to the incorporation of Fe.

In this study, reduced graphene oxide (RGO) supported N-doped porous carbon-coated NiFe alloy composite (NiFe@NC/RGO) was synthesized through in-situ growth of nitrogen-rich MOF of NiFe(CN)₅NO on RGO sheets followed by annealing under Ar atmosphere. Such a chemically robust structure with NiFe nanoalloy encapsulated by N-doped porous carbon supported on RGO can effectively protect the active component from agglomeration, and promote sufficient contact between the active species and electrolyte. Moreover, RGO in the composites can improve the electron conductivity, facilitating quick electron transfer. As expected, the as-synthesized NiFe@NC/RGO composites show excellent electrocatalytic performance for OER with a low overpotential of 223 mV at current density of 10 mA cm⁻², and a small Tafel slope of 48.7 mV dec⁻¹ in 1 M KOH, which is superior to the commercial precious metal oxide catalyst of RuO₂ as well as most of the electrocatalysts reported so far.

Section snippets

Materials

Natural flake graphite (45 μm, 99.95%) were purchased from Aladdin Chemistry Co. Ltd., China. Other chemicals adopted in this experiment were purchased from Sinopharm Chemical Reagent Co. Ltd. All the chemicals were of analytical grade and used as received without further purification. Deionized (DI) water was used through the experiments. A modified Hummers method was adopted for the preparation of graphite oxide [31].

Preparation of the precursors of NiFe(CN)₅NO/GO

A certain amount of graphite oxide was dispersed in 100 mL of DI water by

Synthesis and characterization

The synthetic process of the NiFe@NC/RGO composites is depicted in Scheme 1. Firstly, graphite oxide was ultrasonically dispersed in deionized water to form GO dispersion. GO is electronegative due to the ionization of oxygen-containing functional groups (-COOH and –OH) on its surface [32]. When Ni(NO₃)₂ was introduced into the GO dispersion, the positively charged Ni²⁺ ions will be anchored on GO nanosheet via electrostatic interaction. Subsequently, Fe(CN)₅NO²⁻ was introduced and reacted with

Conclusion

In summary, RGO-supported N-doped porous carbon-coated NiFe alloy nanoparticle composites were synthesized by a convenient one-step annealing method. The NiFe@NC/RGO-240 composite exhibits outstanding OER catalytic performance with an overpotential of 223 mV at 10 mA cm⁻² and a low Tafel value of 48.7 mV dec⁻¹ in 1.0 M KOH. In addition, long-term cycling test verified its good durability. The superior electrocatalytic performance can be attributed to the following aspects: (1) The involved GO

Declaration of Competing Interest

There are no conflicts to declare.

Acknowledgements

We are grateful for financial support from the National Natural Science Foundation of China (Nos. 21875091, 21776115 and 51602129), and the Natural Science Foundation of Jiangsu Province (Nos. BK20171295 and BK20161343).

References (63)

L. Du et al.
Nano Energy
(2017)
S. Anantharaj et al.
Nano Energy
(2017)
X. Shang et al.
Appl. Surf. Sci.
(2016)
X. Li et al.
Electrochim. Acta
(2016)
J.Q. Chi et al.
Appl. Surf. Sci.
(2017)
M. Lee et al.
Appl. Catal. B Environ.
(2018)
J.Q. Chi et al.
Int. J. Hydrog. Energy
(2017)
S.K. Wu et al.
Carbon
(2017)
X.B. Yang et al.
Nano-Micro Letters
(2018)
W. Lingling et al.
Sol. Energy Mater. Sol. Cells
(2018)

Z. Wang et al.

J. Colloid Interf. Sci.

(2013)

M.T. Liu et al.

Int. J. Hydrogen Energ.

(2017)

H.J. Zhang et al.

Int. J. Hydrogen Energ.

(2014)

C.S. Song et al.

J. Colloid Interf. Sci.

(2018)

M. Lee et al.

Appl. Catal. B Environ.

(2018)

X.Y. Yue et al.

J. Colloid Interf. Sci.

(2019)

J.L. Liu et al.

Nano Energy

(2017)

A.J. Esswein et al.

Chem. Rev.

(2007)

N. Armaroli et al.

Angew. Chem. Int. Ed.

(2007)

T. Audichon et al.

J. Phys. Chem. C

(2016)

Y. Lee et al.

J. Phys. Chem. Lett.

(2012)

G.X. Zhu et al.

ACS Appl. Mater. Interfaces

(2018)

S. Wang et al.

Nanoscale

(2017)

J.D. Chen et al.

ACS Catal.

(2018)

G.F. Chen et al.

Adv. Funct. Mater.

(2016)

H. Li et al.

Small

(2018)

Y. Zhou et al.

Small

(2018)

C.C.L. McCrory et al.

J. Am. Chem. Soc.

(2013)

X.G. Wang et al.

J. Mater. Chem. A

(2016)

B.W. Zhang et al.

ACS Appl. Mater. Interfaces

(2018)

M. Eddaoudi et al.

J. Am. Chem. Soc.

(2000)

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Full length articleReduced graphene oxide supported nitrogen-doped porous carbon-coated NiFe alloy composite with excellent electrocatalytic activity for oxygen evolution reaction

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Preparation of the precursors of NiFe(CN)5NO/GO

Synthesis and characterization

Conclusion

Declaration of Competing Interest

Acknowledgements

Nano Energy

Nano Energy

Appl. Surf. Sci.

Electrochim. Acta

Appl. Surf. Sci.

Appl. Catal. B Environ.

Int. J. Hydrog. Energy

Carbon

Nano-Micro Letters

Sol. Energy Mater. Sol. Cells

J. Colloid Interf. Sci.

Int. J. Hydrogen Energ.

Int. J. Hydrogen Energ.

J. Colloid Interf. Sci.

Appl. Catal. B Environ.

J. Colloid Interf. Sci.

Nano Energy

Chem. Rev.

Angew. Chem. Int. Ed.

J. Phys. Chem. C

J. Phys. Chem. Lett.

ACS Appl. Mater. Interfaces

Nanoscale

ACS Catal.

Adv. Funct. Mater.

Small

Small

J. Am. Chem. Soc.

J. Mater. Chem. A

ACS Appl. Mater. Interfaces

J. Am. Chem. Soc.

Full length article
Reduced graphene oxide supported nitrogen-doped porous carbon-coated NiFe alloy composite with excellent electrocatalytic activity for oxygen evolution reaction

Preparation of the precursors of NiFe(CN)₅NO/GO