Electrochemical Ammonia Synthesis—The Selectivity Challenge

Singh, Aayush R.; Rohr, Brian A.; Schwalbe, Jay A.; Cargnello, Matteo; Chan, Karen; Jaramillo, Thomas F.; Chorkendorff, Ib; Nørskov, Jens K.

doi:10.1021/acscatal.6b03035

Cited by 786 publications

(698 citation statements)

References 39 publications

(49 reference statements)

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“…Electron transfer regulation can limit surface dihydrogen formation by simultaneously weakening *H adsorption and reducing electron availability. As reported by Nørskov and co‐workers, this strategy impeded HER and enhanced NRR selectivity (see Figure f) . According to the qualitative model described by these authors, outside a metal surface at normal proton concentrations, HER will always be the dominant reaction.…”

Section: Design Principles For Electrocatalystssupporting

confidence: 54%

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Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

et al. 2020

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Ammonia (NH3) is a pivotal precursor in fertilizer production and a potential energy carrier. Currently, ammonia production worldwide relies on the traditional Haber–Bosch process, which consumes massive energy and has a large carbon footprint. Recently, electrochemical dinitrogen reduction to ammonia under ambient conditions has attracted considerable interest owing to its advantages of flexibility and environmental friendliness. However, the biggest challenge in dinitrogen electroreduction, i.e., the low efficiency and selectivity caused by poor specificity of electrocatalysts/electrolytic systems, still needs to be overcome. Although substantial progress has been made in recent years, acquiring most available electrocatalysts still relies on low efficiency trial‐and‐error methods. It is thus imperative to establish some critical guiding principles for nitrogen electroreduction toward a rational design and accelerated development of this field. Herein, a basic understanding of dinitrogen electroreduction processes and the inherent relationships between adsorbates and catalysts from fundamental theory are described, followed by an outline of the crucial principles for designing efficient electrocatalysts/electrocatalytic systems derived from a systematic evaluation of the latest significant achievements. Finally, the future research directions and prospects of this field are given, with a special emphasis on the opportunities available by following the guiding principles.

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Section: Design Principles For Electrocatalystssupporting

confidence: 54%

Section: Design Principles For Electrocatalystsmentioning

confidence: 99%

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

et al. 2020

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“…Some recent strategies proposed for suppressing the HER and improving the selectivity towards the electrochemical reduction of nitrogen could also be applied to CO 2 RR. [111] These strategies involve limiting the proton and electron transfer rate to the active sites and by doing this, target adsorbates can better compete with H* and develop appreciable surface coverage. However, the option of hydrogen evolution simultaneously with CO 2 reduction for Fisher-Tropsch type application should not be ruled out and it would be appropriate to review the feasibility of producing Fisher-Tropsch feedstock via electrochemical CO 2 reduction.…”

Section: Discussionmentioning

confidence: 99%

Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO₂

Vasileff

Zheng

Qiao

2017

Advanced Energy Materials

347

222

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The electrochemical reduction of CO2 to useful molecules offers an elegant technological solution to current energy security and sustainability issues because it sequesters carbon from the atmosphere, provides an energy storage solution for intermittent renewable sources, and can be used to produce fuels and industrial chemicals. Nanostructured carbon materials have been extensively used to catalyse some key electrochemical processes because of their excellent electrical conductivity, chemical stability, and abundant active sites. This progress report focuses on nanostructured carbon materials, namely graphene materials, carbon nanotubes, porphyrin materials, nanodiamond, and glassy carbon, which have recently shown promise as high performing CO2 reduction electrocatalysts and supports. Along with discussion regarding materials synthesis, structural characterisation, and electrochemical performance characterisation techniques used, this report will discuss the findings of recent computational CO2RR studies which have been key to elucidating active sites and reaction mechanisms, and developing strategies to break conventional scaling relationships. Lastly, challenges and future perspective of these carbon‐based materials for CO2 reduction applications will be given. Much work is still required to realise the commercial viability of the technology, but advanced experimental techniques coupled with theoretical calculations are expected to facilitate future development of the technology.

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“…[24] In this context, targeted design of ar eactive heterogeneousc atalyst surfacea long with rational development of as uitable electrochemicale nvironmenti su rgently required to boost the NRR catalytic activity and selectivity.H owever,v ery limited strategies have been demonstrated so far to suppress HER and improve NRR, especially for the direct electrocatalytic NH 3 synthesis from N 2 and H 2 Ow ith non-precious-metal catalystsa tr oom temperature and atmospheric pressure. The major reason for the low FE that has been reported for the electrochemical N 2 reduction and NH 3 formation in waterfed devices is that the hydrogen evolution reaction(HER) dominates at the operating potential requiredf or NRR.…”

Section: Introductionmentioning

confidence: 99%

Highly Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure over Iron Oxide Catalysts

Cui

Tang

Liu

et al. 2018

Chemistry A European J

135

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The catalytic conversion of dinitrogen (N ) into ammonia under ambient conditions represents one of the Holy Grails in sustainable chemistry. As a potential alternative to the Haber-Bosch process, the electrochemical reduction of N to NH is attractive owing to its renewability and flexibility, as well as its sustainability for producing and storing value-added chemicals from the abundant feedstock of water and nitrogen on earth. However, owing to the kinetically complex and energetically challenging N reduction reaction (NRR) process, NRR electrocatalysts with high catalytic activity and high selectivity are rare. In this contribution, as a proof-of-concept, we demonstrate that both the NH yield and faradaic efficiency (FE) under ambient conditions can be improved by modification of the hematite nanostructure surface. Introducing more oxygen vacancies to the hematite surface renders an improved performance in NRR, which leads to an average NH production rate of 0.46 μg h cm and an NH FE of 6.04 % at -0.9 V vs. Ag/AgCl in 0.10 m KOH electrolyte. The durability of the electrochemical system was also investigated. A surprisingly high average NH production rate of 1.45 μg h cm and a NH FE of 8.28 % were achieved after the first 1 h chronoamperometry test. This is among the highest FEs reported so far for non-precious-metal catalysts that use a polymer-electrolyte-membrane cell and is much higher than the FE of precious-metal catalysts (e.g., Ru/C) under comparable reaction conditions. However, the NH yield and the FE dropped to 0.29 μg h cm and 2.74 %, respectively, after 16 h of chronoamperometry tests, which indicates poor durability of the system. Our results demonstrate the important role that the surface states of transition-metal oxides have in promoting electrocatalytic NRR under ambient conditions. This work may spur interest towards the rational design of electrocatalysts as well as electrochemical systems for NRR, with emphasis on the issue of stability.

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Electrochemical Ammonia Synthesis—The Selectivity Challenge

Cited by 786 publications

References 39 publications

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO₂

Highly Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure over Iron Oxide Catalysts

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Electrochemical Ammonia Synthesis—The Selectivity Challenge

Cited by 786 publications

References 39 publications

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO2

Highly Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure over Iron Oxide Catalysts

Contact Info

Product

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Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO₂