Sulfurization enhancement of FeMoO4 for electrochemical ammonia synthesis with high Faradaic efficiency in neutral media

A VN nanowire array on carbon cloth (VN/CC) as a high-performance catalyst for the nitrogen reduction reaction (NRR) affords high ammonia yield (2.48 × 10−10 mol−1 s−1 cm−2) and faradaic efficiency (3.58%) at −0.3 V versus RHE in 0.1 M HCl.

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Graphdiyne based metal atomic catalysts for synthesizing ammonia

National Science Review ◽

10.1093/nsr/nwaa213 ◽

2020 ◽

Cited By ~ 1

Author(s):

Huidi Yu ◽

Yurui Xue ◽

Lan Hui ◽

Chao Zhang ◽

Yan Fang ◽

...

Keyword(s):

Density Functional Theory ◽

Electron Transfer ◽

Density Functional ◽

Reaction Pathway ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Faradaic Efficiency ◽

Nitrogen Reduction ◽

Strongly Coupled ◽

Neutral Media

Abstract Exploring new catalysts for nitrogen reduction at ambient pressures and temperatures with ultrahigh ammonia (NH3) yield and selectivity is still a giant challenge. In this work, atomic catalysts with separated Pd atoms on graphdiyne (Pd-GDY) have been synthesized and show fascinating electrocatalytic properties for nitrogen reduction. Outstandingly, the catalyst shows the highest average NH3 yield of 4.45 ± 0.30 mgNH3 mgPd−1 h−1, almost tens of orders larger than previously reported ones, and 100% reaction selectivity in neutral media. And Pd-GDY exhibits almost no decreases in the NH3 yield and Faradaic efficiency. Density functional theory calculations show that the reaction pathway prefers to perform at the (Pd, C1, C2) active area due to the strongly coupled (Pd, C1, C2) which elevates the selectivity via enhanced electron-transfer. By adjusting the p-d coupling accurately, the reduction of self-activated nitrogen is promoted by anchoring atom selection, and the side effects are minimized.

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Boosting Electrochemical Nitrogen Reduction to Ammonia with High Efficiency using LiNb3O8 Electrocatalyst in Neutral Media

Dalton Transactions ◽

10.1039/d1dt03284d ◽

2022 ◽

Author(s):

Qi Wang ◽

Shuhui Fan ◽

Leran Liu ◽

Xiaojiang Wen ◽

Yun Wu ◽

...

Keyword(s):

High Efficiency ◽

Ammonia Synthesis ◽

Reduction Reaction ◽

Nitrogen Reduction ◽

Bosch Process ◽

Neutral Media

Nitrogen reduction reaction (NRR) has great research prospects as a method to replace the industrial Haber-Bosch process for ammonia synthesis. Nevertheless, the efficiency of NRR is mainly depended on the...

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Salting-out effect promoting highly efficient ambient ammonia synthesis

Nature Communications ◽

10.1038/s41467-021-23360-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Mengfan Wang ◽

Sisi Liu ◽

Haoqing Ji ◽

Tingzhou Yang ◽

Tao Qian ◽

...

Keyword(s):

Hydrogen Evolution ◽

Ammonia Synthesis ◽

Hydration Shell ◽

Reduction Process ◽

Salting Out ◽

Promising Alternative ◽

Faradaic Efficiency ◽

Concept System ◽

Highly Efficient ◽

Low Activity

AbstractThe electroreduction of nitrogen to ammonia offers a promising alternative to the energy-intensive Haber–Bosch process. Unfortunately, the reaction suffers from low activity and selectivity, owing to competing hydrogen evolution and the poor accessibility of nitrogen to the electrocatalyst. Here, we report that deliberately triggering a salting-out effect in a highly concentrated electrolyte can simultaneously tackle the above challenges and achieve highly efficient ammonia synthesis. The solute ions exhibit strong affinity for the surrounding H2O molecules, forming a hydration shell and limiting their efficacy as both proton sources and solvents. This not only effectively suppresses hydrogen evolution but also ensures considerable nitrogen flux at the reaction interface via heterogeneous nucleation of the precipitate, thus facilitating the subsequent reduction process in terms of both selectivity and activity. As expected, even when assembled with a metal-free electrocatalyst, a high Faradaic efficiency of 71 ± 1.9% is achieved with this proof-of-concept system.

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Electrocatalytic Activity of Lanthanum Chromite-Based Composite Cathode for Ammonia Synthesis from Water and Nitrogen

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1160.65 ◽

2021 ◽

Vol 1160 ◽

pp. 65-74

Author(s):

Ibrahim A. Amar ◽

Mohammed M. Ahwidi

Keyword(s):

Noble Metal ◽

Electrocatalytic Activity ◽

Ammonia Synthesis ◽

Formation Rate ◽

Sol Gel ◽

Composite Cathode ◽

Perovskite Oxide ◽

Synthesis Process ◽

Lanthanum Chromite ◽

Faradaic Efficiency

The electrocatalytic ammonia synthesis using water (along with nitrogen) as a hydrogen source is proposed as an alternative green and clean technology to the energy-intensive and CO2-emitting process (Haber-Bosch) for ammonia production. Besides, a selective electrocatalyst for ammonia synthesis versus the competing hydrogen evolution remains elusive. This study aims to investigate the electrocatalytic activity of non-noble metal Co and Fe-free perovskite oxide-based composite cathode (La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ) towards ammonia synthesis from H2O and N2. The electrocatalyst was synthesized via a sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully with a maximum formation rate of 2.5 × 10-10 mol s-1 cm-2 and Faradaic efficiency of 0.52% at 400 oC and applied voltage of 1.4 V. The results demonstrated that the proposed non-noble metal-based electrocatalyst is a promising material for the carbon-free ammonia synthesis process.

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Synthesis of Ammonia Directly from Air and Water via a Single-Chamber Reactor Using Lanthanum Chromite-Based Composite as an Electrocatalyst

Nano Hybrids and Composites ◽

10.4028/www.scientific.net/nhc.32.35 ◽

2021 ◽

Vol 32 ◽

pp. 35-44

Author(s):

Ibrahim A. Amar ◽

Mohammed M. Ahwidi

Keyword(s):

Noble Metal ◽

Ammonia Synthesis ◽

Direct Synthesis ◽

Formation Rate ◽

Lanthanum Chromite ◽

Ammonia Production ◽

Faradaic Efficiency ◽

Single Chamber ◽

Promising Technology ◽

Ammonia Formation

Carbon-free electrosynthesis of ammonia using water (H2 source) and air (N2 source) is promising technology to reduce the global CO2 emission resulting from the industrial ammonia production process (Haber-Bosch). In this study, electrocatalysis activity of non-noble metal perovskite-based catalyst (La0.75Sr0.25Cr0.5Fe0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ, LSCrF-CGDC) for ammonia synthesis directly from air and water was explored. Ammonia was successfully from wet air (3%H2O) synthesized in a single-chamber type reactor. The highest ammonia formation rate and Faradaic efficiency of about 1.94×10-11 mol s-1 cm-2 and 2.01% were achieved at 375 oC and 1.2 V, respectively. The observed ammonia formation rate is higher than reported for an expensive noble metal-based catalyst (Ru/MgO). The obtained results indicated that the direct synthesis of ammonia from air and water is a promising technology for green and sustainable ammonia synthesis.

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Electrochemical ammonia synthesis via nitrate reduction on Fe single atom catalyst

Nature Communications ◽

10.1038/s41467-021-23115-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhen-Yu Wu ◽

Mohammadreza Karamad ◽

Xue Yong ◽

Qizheng Huang ◽

David A. Cullen ◽

...

Keyword(s):

Nitrate Reduction ◽

Density Functional ◽

Ammonia Synthesis ◽

Reaction Pathway ◽

Density Functional Theory Calculations ◽

Single Atom ◽

Functional Theory ◽

Faradaic Efficiency ◽

Yield Rate ◽

Water Pollutant

AbstractElectrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis, and can be an appealing and supplementary alternative to the Haber-Bosch process. However, as there are other nitrate reduction pathways present, selectively guiding the reaction pathway towards ammonia is currently challenged by the lack of efficient catalysts. Here we report a selective and active nitrate reduction to ammonia on Fe single atom catalyst, with a maximal ammonia Faradaic efficiency of ~ 75% and a yield rate of up to ~ 20,000 μg h−1 mgcat.−1 (0.46 mmol h−1 cm−2). Our Fe single atom catalyst can effectively prevent the N-N coupling step required for N2 due to the lack of neighboring metal sites, promoting ammonia product selectivity. Density functional theory calculations reveal the reaction mechanisms and the potential limiting steps for nitrate reduction on atomically dispersed Fe sites.

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Bismuth-Based Free-Standing Electrodes for Ambient-Condition Ammonia Production in Neutral Media

Nano-Micro Letters ◽

10.1007/s40820-020-00444-y ◽

2020 ◽

Vol 12 (1) ◽

Cited By ~ 4

Author(s):

Ying Sun ◽

Zizhao Deng ◽

Xi-Ming Song ◽

Hui Li ◽

Zihang Huang ◽

...

Keyword(s):

Low Cost ◽

Catalytic Performance ◽

Reduction Reaction ◽

Ambient Conditions ◽

Free Standing ◽

Hydrogen Electrode ◽

Faradaic Efficiency ◽

Long Term Stability ◽

High Efficient ◽

Neutral Media

AbstractElectrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions. Here, we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene (Bi2O3/FEG) via a facile electrochemical deposition method. The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2% and a large NH3 yield of 4.21 ± 0.14 $$ \upmu{\text{g}}_{{{\text{NH}}_{3} }} $$ μ g NH 3 h−1 cm−2 at − 0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4, better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, binder-free characteristic, and facile electron transfer, Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts. This study is significant to design low-cost, high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.

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Bimetallic metal–organic framework-derived MoFe-PC microspheres for electrocatalytic ammonia synthesis under ambient conditions

Journal of Materials Chemistry A ◽

10.1039/c9ta10524g ◽

2020 ◽

Vol 8 (4) ◽

pp. 2099-2104 ◽

Cited By ~ 5

Author(s):

Silong Chen ◽

Haeseong Jang ◽

Jia Wang ◽

Qing Qin ◽

Xien Liu ◽

...

Keyword(s):

Porous Structure ◽

Active Sites ◽

Ammonia Synthesis ◽

Metal Organic Framework ◽

High Yield ◽

Ambient Conditions ◽

Faradaic Efficiency ◽

Yield Rate ◽

Metal Organic ◽

Organic Framework

MoFe-PC exhibits a high yield rate and faradaic efficiency for NH3 electrosynthesis in acidic electrolytes due to the multicomponent active sites and inherent porous structure.

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