FeNi@CNS nanocomposite as an efficient electrochemical catalyst for N2-to-NH3 conversion under ambient conditions

doi:10.1016/j.jmst.2021.05.083

Journal of Materials Science & Technology

Volume 103, 20 March 2022, Pages 59-66

https://doi.org/10.1016/j.jmst.2021.05.083 Get rights and content

Highlights

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FeNi@CNS nanocomposite was synthesized by a simple water bath process.
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The FeNi@CNS nanocomposite showed great catalytic activity towards high faradaic efficiency, NRR to NH3 synthesis.
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The strong chemical interaction between Fe and Ni plays a key role in the electrochemical activities.
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The FeNi@CNS nanocomposite could serve as an active and durable NRR catalyst in 0.1 M Na2SO4 solution.

Abstract

The electrocatalytic nitrogen reduction reaction (NRR) has emerged as a promising renewable energy source and a feasible strategy as an alternative to Haber-Bosch ammonia (NH₃) synthesis. However, finding an efficient and cost-effective robust catalyst to activate and cleave the extremely strong triple bond in nitrogen (N₂) for electrocatalytic NRR is still a challenge. Herein, a FeNi@CNS nanocomposite as an efficient catalyst for N₂ fixation under ambient conditions is designed. This FeNi@CNS nanocomposite was prepared by a simple water bath process and post-calcination. The FeNi@CNS is demonstrated to be a highly efficient NRR catalyst, which exhibits better NRR performance with exceptional Faradaic efficiency of 9.83% and an NH₃ yield of 16.52 μg h⁻¹ cm⁻² in 0.1 M Na₂SO₄ aqueous solution. Besides, high stability and reproducibility with consecutive 6 cycles for two hours are also demonstrated throughout the NRR electrocatalytic process for 12 h. Meanwhile, the FeNi@CNS catalyst encourages N₂ adsorption and activation as well as effectively suppressing competitive HER. Therefore, this earth-abundant FeNi@CNS catalyst with a subtle balance of activity and stability has excellent potential in NRR industrial applications.

Graphical abstract

FeNi@CNS nanocomposite as an efficient catalyst for N2 fixation under ambient conditions.

Introduction

Ammonia (NH₃) is one of the most prevalent organic chemicals in industry and agriculture worldwide and is a renewable alternative to fossil fuels due to its useful properties as a chemical energy carrier [1], [2], [3]. As compared to other compounds, NH₃ is also an important industrial chemical that serves as a major carrier of hydrogen energy, is relatively safe, environmentally friendly, and most importantly, does not emit CO₂ [4], [5], [6]. Traditionally, most of the synthetic NH₃ is produced on an industrial scale via the Haber−Bosch process, which requires extreme temperatures and pressure to break the molecular nitrogen (N₂) [7], [8], [9], [10]. However, NH₃ production uses fossil fuels and results in air pollutants produced as a by-product [11,12]. It is necessary to explore new approaches to N₂ fixation at ambient conditions to produce NH₃ [13], [14], [15]. Electrochemical N₂ fixation to NH₃ is a fascinating process with low energy consumption under environmental conditions and could become a viable alternative to the Haber-Bosch method [16], [17], [18]. Electrochemical nitrogen reduction reaction (NRR) is an attractive alternative approach to produce nitrogen-induced NH₃ (i.e., N₂ + 6H⁺ + 6e⁻ → 2NH₃) under mild conditions [19,20]. Generally, the first major stage in the NRR process is the chemisorption of the N₂ molecule on the catalytic surface. The electrochemical NRR could weaken the inert N triple bond N bond but does not separate it, specifically through multiple progressive steps of protonation.

The electrocatalytic NRR has gained a great deal of research interest over the last few years [21], [22], [23], [24]. However, the initiation of fiercely aggressive identical hydrogen evolution reaction (HER) in an aqueous electrolyte causes the main hindrance and rivalry for efficient NRR [20,25,26]. Besides, the pursuit of efficient NRR with a high NH₃ yield and Faradaic performance (FE) at the same time remains a major challenge, particularly in low-cost aqueous electrolytes [27]. Therefore, catalysts play a crucial role in the electrochemical NRR, breaking the extremely stable nitrogen triple bond in N₂ and slower reaction kinetics. The efficiency of electrocatalytic NRR depends largely on the structure, components, and surface morphology of the electrocatalysts. Recently, various studies have reported efficient electrocatalysts for NRR, including platinum-group-metals (PGM) such as Au [28], [29], [30], Pd [31], and Ru as well as transition metals FeB₂ [32], Fe₃C@C [33], Fe, MoN/C [34], MoO [35], 1T@2H MoSe₂ [36], VN [37] etc., and metals free materials [38]. PGM, for example, has good performance but is difficult to obtain due to its higher price, limiting its industrial applications [22,31,39,40]. To this end, the design of good NRR catalysts is urgently needed for the efficient activation and reduction of nitrogen to ammonia under ambient conditions.

However, many transition metals (TMs) catalysts have recently played a vital role in the electrocatalytic NRR, mainly consisting of metal alloys, metal oxides, and metal carbides/nitrides dichalcogenides [21,41,42]. These transition metals have shown better binding strength to the N₂ molecule due to the combination of empty and filled "d" orbitals [43,44]. Usually, transition metal gives up lone pairs of electrons to the nitrogen orbital, contributing to the weakening of N triple bond N bonds [45,46]. Simultaneously, much effort has been invested in the TMs electrocatalytic NRR to increase the NH₃ formation rate. In electrocatalytic NRR, the competitive hydrogen evolution reaction (HER) using low-HER catalytic converters may likely improve NRR efficiency for high NH₃ yield [47], [48], [49]. For instance, Wang et al. developed a Fe–N/C–carbon nanotube (CNT) catalyst through a metal-organic framework synthetic method, which demonstrated more efficient and stable NRR electrocatalyst activity and expanded the potential of transition metal-based nanomaterials in NRR applications [50]. Various approaches have been used to suppress hydrogen absorption on the catalytic surface, such as the engineering surface vacancy and the rational design of an efficient and stable NRR electrocatalyst.

TMs have been demonstrated to be chemically stable when coupled with conductive carbon-based support to enhance catalytic activity [51,52]. Carbon-based material helps increase electrical interaction with the current collector to improve the transfer of electrons to active sites, preventing the agglomeration of nanomaterials [53,54]. This work demonstrates an effective and facile method of fabricating the FeNi@CNS nanocomposites as efficient non-PGM electrocatalyst in N₂ to NH₃ fixation with good selectivity and high NH₃ yield rate.

Section snippets

Materials

Ferric chloride hexahydrate (FeCl₃·6H₂O), nickel chloride hexahydrate (NiCl₂·6H₂O), succinic acid (C₄H₆O₄), potassium hydroxide (KOH), sodium hypochlorite solution (NaClO), trisodium citrate dehydrate (C₆H₅Na₃O₇·2H₂O), isopropanol, para-(dimethylamino) benzaldehyde (C₉H₁₁NO), ammonium chloride (NH₄Cl), acetone (CH₃COCH₃), hydrazine hydrate (N₂H₄·H₂O, 85%), sodium hydroxide (NaOH), and ethanol (C₂H₅OH) were purchased from Aladdin Chemistry Co., Ltd. (Shanghai, China). Sodium nitroferricyanide

Results and discussion

The synthesis process of the FeNi@CNS nanocomposite is shown in Fig. 1. The whole process for FeNi@CNS nanocomposites synthesis was carried out via a simple method of water bath synthesis at 80 °C for 4 h. The bimetallic nanocomposite was obtained with a carbon scaffold to convert Ni²⁺ and Fe³⁺ ions into FeNi nanoparticles (NPs) followed by a simple annealing process for 2 h at 800 °C under Ar gas. The final product FeNi nanoparticles (FeNi NPs) are grafted on the surface of a porous carbon

Electrochemical performance

The electrochemical activity performances of the FeNi@CNS nanocomposites on the electrochemical reduction of N₂ were measured in the typical three-electrode electrochemical workstation setup. The electrocatalytic NRR was conducted using FeNi@CNS nanocomposite as a cathode, and the Pt sheet acted as an anode. The two chambers are divided by the anionic membrane, as seen in Fig. 4(a) in the schematic diagram. The 40 sccm of N₂ gas flow rate passed through the gas channel during the test. When the

Conclusion

In summary, FeNi@CNS nanocomposite prepared by a simple water bath followed by annealing has been demonstrated to be an efficient NRR electrocatalyst under ambient conditions for the first time. The FeNi NPs are grafted homogeneously on porous carbon nanosheets (CNS). The FeNi@CNS nanocomposite achieves a 9.83% of FE and 16.52 μg h ⁻ ¹ cm⁻² NH₃ yield rate in 0.1 M Na₂SO₄ solution with a relatively low overpotential of −0.2 V. This electrocatalyst has excellent durability and electrochemical

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgment

Liang Qiao acknowledges the research support by the National Natural Science Foundation of China (No. 11774044).

References (67)

Y. Xue et al.
Nat. Commun.
(2018)
A. Mavlonov et al.
Sol. Energy
(2020)
H. Wu et al.
J. Energy Chem.
(2021)
X. Hu et al.
Appl. Catal. B Environ.
(2021)
Y. Zhang et al.
J. Colloid Interface Sci.
(2021)
Y. Guo et al.
Nano Energy
(2020)
Y. Wang et al.
J. Catal.
(2020)
Y. Luo et al.
Efficient Electrocatalytic N2 Fixation with MXene under Ambient Conditions
Joule
(2019)
C. Shuai et al.
Appl. Surf. Sci.
(2020)
X. Guo et al.
J. Power Sources
(2020)

M. Hattori et al.

Nat. Commun.

(2020)

Z. Yan et al.

Adv. Energy Mater.

(2020)

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Research ArticleFeNi@CNS nanocomposite as an efficient electrochemical catalyst for N2-to-NH3 conversion under ambient conditions

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Results and discussion

Electrochemical performance

Conclusion

Declaration of Competing Interest

Acknowledgment

Nat. Commun.

Sol. Energy

J. Energy Chem.

Appl. Catal. B Environ.

J. Colloid Interface Sci.

Nano Energy

J. Catal.

Joule

Appl. Surf. Sci.

J. Power Sources

Electrochim. Acta

J. Energy Chem.

Appl. Surf. Sci.

Mater. Des.

Nano Energy

Appl. Catal. B Environ.

J. Hazard. Mater.

Appl. Catal. B Environ.

Chin. Chem. Lett.

Appl. Catal. B Environ.

Appl. Catal. B Environ.

Chem. Eng. J.

Chem. Eng. J.

Appl. Surf. Sci.

J. Energy Chem.

Appl. Catal. B Environ.

J. Power Sources

Appl. Catal. B Environ.

Nature

Nat. Catal.

J. Mater. Chem. C

Nat. Commun.

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Research Article
FeNi@CNS nanocomposite as an efficient electrochemical catalyst for N₂-to-NH₃ conversion under ambient conditions