Electrochemical Synthesis of Ammonia in Molten Salt Electrolyte Using Hydrogen and Nitrogen at Ambient Pressure

Biçer, Yusuf; Dinçer, İbrahim

doi:10.1149/2.0091708jes

Cited by 34 publications

(19 citation statements)

References 29 publications

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“…In this vein, it was proposed [4] that cells operating in the 200–250 °C range, e.g., with CsH 2 PO 4 electrolytes, might be ideal for ammonia synthesis. The data of Table 1, however, show otherwise, with most such systems struggling to reach 10 −10 mol·s −1 ·cm −2 and only three achieving FE > 1% [15,19,20]. While these underwhelming results might be attributed to the poor design and/or fabrication of the cathode or the electrode-electrolyte interphase, it may simply be that NRR kinetics at ambient pressure are still too slow, even at 250 °C.…”

Section: Discussionmentioning

confidence: 99%

“…Figure 4 is a schematic diagram of the apparatus used by Y. Bicer and I. Dincer [20]. The electrolyte was a molten salt (NaOH-KOH) and two porous nickel mesh electrodes were used for anode and cathode.…”

Section: Recent Experimental Findingsmentioning

confidence: 99%

“…Experiments were conducted in the range of 200–255 °C with suspended Fe 3 O 4 nanoparticles used as the catalyst. The optimum operating temperature was 200 °C, at which the ammonia production rate of 6.54 × 10 −10 mol·s −1 ·cm −2 was obtained with a corresponding FE of 9.3% [20].…”

Section: Recent Experimental Findingsmentioning

confidence: 99%

“…The reason for this moderate success is that the proposed alternatives successfully solve one and not all the problems. For example, the works with molten salts [19,20] bypass the problem of hydrogen evolution at the cathode because the reaction of N 3− with H 2 takes place at the anode (Figure 4). Nevertheless, the FE, which in this case is defined as the moles of NH 3 /s produced, divided by I/3F, was lower than 9.5% and 13.7% in [13] and [16], respectively.…”

Section: The Outlookmentioning

confidence: 99%

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Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

et al. 2019

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Ammonia is a key chemical produced in huge quantities worldwide. Its primary industrial production is via the Haber-Bosch method; a process requiring high temperatures and pressures, and consuming large amounts of energy. In the past two decades, several alternatives to the existing process have been proposed, including the electrochemical synthesis. The present paper reviews literature concerning this approach and the experimental research carried out in aqueous, molten salt, or solid electrolyte cells, over the past three years. The electrochemical systems are grouped, described, and discussed according to the operating temperature, which is determined by the electrolyte used, and their performance is valuated. The problems which need to be addressed further in order to scale-up the electrochemical synthesis of ammonia to the industrial level are examined.

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Section: Discussionmentioning

confidence: 99%

Section: Recent Experimental Findingsmentioning

confidence: 99%

Section: Recent Experimental Findingsmentioning

confidence: 99%

Section: The Outlookmentioning

confidence: 99%

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Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

et al. 2019

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“…[7][8][9][10] If electricity is supplied from clean energy sourcess uch as solar,w ind, geothermal, or hydropower,t he electrochemical process can successfully use renewable energy for ammonia synthesis. [11,12] Despite all the effortst oi mprovet he thermodynamics and optimize the rate and efficiency of NH 3 formation, [13][14][15][16][17][18][19][20][21][22][23][24] achieving production rates suitable for commercialization (4.3-8.7 10 À7 mol s À1 cm À2 with efficiencies > 50 %) [8] under ambient conditions is still a challenge. The nitrogen reduction reaction (NRR) to ammonia in aqueous electrolytes under ambient conditions is challenging owing to the exceptionals tability of the N 2 triple bond along with the presence of the hydrogen evolution reaction (HER) as ac ompeting side reaction.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic Nitrogen Fixation Catalyzed by Transition Metal Sulfide Surfaces in an Electrolytic Cell

2019

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The nitrogen reduction reaction was investigated on the surfaces of 18 different stable transition metal sulfides using density functional theory calculations. YS, ScS, and ZrS were modeled in the rocksalt structure with the (1 0 0) facet; TiS, VS, CrS, NbS, NiS, and FeS in NiAs‐type structure with the (1 1 1) facet; and MnS2, CoS2, IrS2, CuS2, OsS2, FeS2, RuS2, RhS2, and NiS2 in pyrite structure for both the (1 0 0) and (1 1 1) orientations. As the first step towards determination of sulfides that are less prone to hydrogen evolution, the competition between adsorption of NNH and H (for the associative mechanism), and between adsorption of N and H (for the dissociative mechanism) on these surfaces was considered. The catalytic activity through both the associative and dissociative mechanisms was explored and the overpotential required for electrochemical ammonia formation is reported. The scaling relations and volcano plots were constructed with free energy of adsorption of NNH or N on the surface as the descriptor. RuS2 was observed as the most active sulfide that could catalyze nitrogen reduction to ammonia at potentials around −0.3 V through the associative mechanism. NbS, CrS, TiS, and VS are also promising candidates for both the associative and dissociative mechanisms with overpotentials for nitrogen reduction around 0.7–1.1 V.

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Lithium‐based Loop for Ambient‐Pressure Ammonia Synthesis in a Liquid Alloy‐Salt Catalytic System

et al. 2021

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The Haber‐Bosch process for ammonia (NH3) production in industry relies on high temperature and high pressure and is therefore highly energy intensive. In addition, the activity of the solid transition metal‐based catalysts used is typically limited by the scaling relation between activation barrier for N2 dissociation and nitrogen‐binding energy. Here, an innovative Li‐based loop in a liquid alloy‐salt catalytic system for ambient‐pressure NH3 synthesis from N2 and H2 was developed. The looping process consisted of three reaction steps taking place simultaneously. The first step was the nitrogen fixation by Li in the liquid Li−Sn alloy to form lithium nitride (Li3N), which floated up and dissolved into the molten salt. The second step was the hydrogenation of the Li3N to produce NH3 and lithium hydride (LiH) in the molten salt. The third step was the decomposition of the LiH to regenerate Li in the presence of Sn. An average NH3 yield rate of 0.025 μg s−1 was achieved in an 81 h test at 510 °C and ambient pressure. The floating and dissolution of Li3N realized in the liquid catalytic system enabled circumventing the scaling relation exerted on Li, and the remarkable properties of liquid alloy and molten salt offered extraordinary advantages for NH3 synthesis at ambient pressure.

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Electrochemical Synthesis of Ammonia in Molten Salt Electrolyte Using Hydrogen and Nitrogen at Ambient Pressure

Cited by 34 publications

References 29 publications

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

Biomimetic Nitrogen Fixation Catalyzed by Transition Metal Sulfide Surfaces in an Electrolytic Cell

Lithium‐based Loop for Ambient‐Pressure Ammonia Synthesis in a Liquid Alloy‐Salt Catalytic System

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