Synthesis of Ammonia at Atmospheric Pressure with the Use of Solid State Proton Conductors

Marnellos, George; Zisekas, S.; Stoukides, Michael

doi:10.1006/jcat.2000.2877

Cited by 118 publications

(87 citation statements)

References 16 publications

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“…An interesting extension to this work was described independently by the Stoukides group 12 and by Vayenas and co-workers. 13 In the system described by the latter authors, a proton-conducting ceramic disc of CaIn 0.1 Zr 0.9 O 3-α was covered on one side with a layer of silver (to act as a hydrogen oxidation catalyst) and on the other side with a commercial iron-based Haber Bosch catalyst.…”

Section: Electrochemical Ammonia Production From N 2 and Hmentioning

confidence: 69%

Recent progress towards the electrosynthesis of ammonia from sustainable resources

2017

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Ammonia (NH 3 ) is a key commodity chemical of vital importance for fertilizers. It is made on an industrial scale via the Haber Bosch process, which requires significant infrastructure to be in place such that ammonia is generally made in large, centralized facilities. If ammonia could be produced under less demanding conditions, then there would be the potential for smaller devices to be used to generate ammonia in a decentralized manner for local consumption. Electrochemistry has been proposed as an enabling technology for this purpose as it is relatively simple to scale electrolytic devices to meet almost any level of demand. Moreover, it is possible to envisage electrosynthetic cells where water could be oxidized to produce protons and electrons at the anode which could then be used to reduce and protonate nitrogen to give ammonia at the cathode. If this nitrogen were sourced from the air, then the only required infrastructure for this process would be supplies of water, air and electricity, the latter of which could be provided by renewables. Hence an electrosynthetic cell for ammonia production could allow NH 3 to be generated sustainably in small, low-cost devices requiring only minimal facilities. In this review, we describe recent progress towards such electrosynthetic ammonia production devices, summarizing also some of the seminal literature in the field. Comparison is made between the various different approaches that have been taken, and the key remaining challenges in the electrosynthesis of ammonia are highlighted.

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Section: Electrochemical Ammonia Production From N 2 and Hmentioning

confidence: 69%

Recent progress towards the electrosynthesis of ammonia from sustainable resources

2017

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“…The only dierence is the change in the free energy of the electrons in the electrode when the electric potential is applied, as given in eqn. 23. By applying an electric potential which raises the free energy of the electrons in the metal electrode and hence drives protons from the electrolyte towards the metal surface, the uphill reaction steps can be eliminated.…”

Section: Applied Potential On a Ru Electrodementioning

confidence: 99%

“…The energy input needed for articial processes is estimated to be as large as for the biological N 2 xation [20]. For the electro-catalytic N 2 reduction, various types of electrolytes and electrode materials have been tried, but the kinetics are too slow for practical applications [21,22,23,24,25,26,27,28]. Little is known about the mechanism of this process and in most cases hydrogen gas is formed more readily than hydrogenation of N 2 .…”

Section: Introductionmentioning

confidence: 99%

A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction

Skúlason

Bligaard

Guðmundsdóttir

et al. 2012

Phys. Chem. Chem. Phys.

1,250

1,468

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Theoretical studies of the possibility of forming ammonia electrochemically at ambient temperature and pressure are presented. Density functional theory calculations were used in combination with the computational standard hydrogen electrode to calculate the free energy prole for the reduction of N 2 admolecules and N adatoms on several close-packed and stepped transition metal surfaces in contact with an acidic electrolyte. Trends in the catalytic activity were calculated for a range of transition metal surfaces and applied potentials under the assumption that the activation energy barrier scales with the free energy dierence in each elementary step. The most active surfaces, on top of the volcano diagrams, are Mo, Fe, Rh, and Ru, but hydrogen gas formation will be a competing reaction reducing the faradaic eciency for ammonia production. Since the early transition metal surfaces, such as Sc, Y, Ti, and Zr bind N-adatoms more strongly than H-adatoms, a signicant production of ammonia compared with hydrogen gas can be expected on those metal electrodes when a bias of -1 V to -1.5 V vs. SHE is applied. Defect-free surfaces of the early transition metals are catalytically more active than their stepped counterparts.

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“…I. The experimental apparatus, the cellreactor as well as the catalyst (electrode) preparation and characterization have been described in detail in previous communications [ 1,2,8]. The reactant NH 3 and the diluent Analysis of the inlet and outlet gas was performed by on-line gas chromatography with a Molecular Sieve 5A…”

Section: Experimental Descriptionmentioning

confidence: 99%

“…In a number of recent reports, the electrochemical synthesis of ammonia in solid electrolyte ceils [1][2][3][4] has been reported. The use of solid-state proton conductors offers the possibility of an alternative route to ammonia synthesis at atmospheric pressure.…”

Section: Introductionmentioning

confidence: 99%

Study of ammonia decomposition in a proton conducting solid electrolyte cell

Zisekas

Karagiannakis

Marnellos

et al. 2002

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Synthesis of Ammonia at Atmospheric Pressure with the Use of Solid State Proton Conductors

Cited by 118 publications

References 16 publications

Recent progress towards the electrosynthesis of ammonia from sustainable resources

Recent progress towards the electrosynthesis of ammonia from sustainable resources

A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction

Study of ammonia decomposition in a proton conducting solid electrolyte cell

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Synthesis of Ammonia at Atmospheric Pressure with the Use of Solid State Proton Conductors

Cited by 118 publications

References 16 publications

Recent progress towards the electrosynthesis of ammonia from sustainable resources

Recent progress towards the electrosynthesis of ammonia from sustainable resources

A theoretical evaluation of possible transition metal electro-catalysts for N2reduction

Study of ammonia decomposition in a proton conducting solid electrolyte cell

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A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction