Single atom catalysis for electrocatalytic ammonia synthesis

2021 ◽  
Author(s):  
Jieying Wan ◽  
Jiageng Zheng ◽  
Hao Zhang ◽  
Angjian Wu ◽  
Xiaodong Li
Keyword(s):  
Ammonia Synthesis ◽  
Single Atom ◽  
Great Success ◽  
Modern Agriculture ◽  
Bosch Process

Ammonia is a vital base molecule for modern agriculture and industry. As the commercially-mature approach for NH3 production, the traditional Haber–Bosch process has achieved great success; however, it also suffers...

Ammonia synthesis by N2 and steam electrolysis in molten hydroxide suspensions of nanoscale Fe2O3

Science ◽  
2014 ◽  
Vol 345 (6197) ◽  
pp. 637-640 ◽  
Author(s):  
Stuart Licht ◽  
Baochen Cui ◽  
Baohui Wang ◽  
Fang-Fang Li ◽  
Jason Lau ◽  
...  
Keyword(s):  
Current Density ◽  
Steam Reforming ◽  
Ammonia Synthesis ◽  
Coulombic Efficiency ◽  
Steam Pressure ◽  
Molar Ratio ◽  
Applied Current ◽  
Bosch Process ◽  
Electron Conversion ◽  
Steam Reforming Of Methane

The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm−2) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm−2 current density decreased to 1.0 V.

scholarly journals Poisoning of Ammonia Synthesis Catalyst Considering Off-Design Feed Compositions

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1225
Author(s):  
Alireza Attari Moghaddam ◽  
Ulrike Krewer
Keyword(s):  
Ammonia Synthesis ◽  
Model Simulation ◽  
Catalyst Activity ◽  
Water Electrolysis ◽  
Gas Composition ◽  
Catalyst Poisoning ◽  
Bosch Process ◽  
Microkinetic Model ◽  
Water Contents ◽  
Hydrogen Stream

Activity of ammonia synthesis catalyst in the Haber-Bosch process is studied for the case of feeding the process with intermittent and impurity containing hydrogen stream from water electrolysis. Hydrogen deficiency due to low availability of renewable energy is offset by increased flow rate of nitrogen, argon, or ammonia, leading to off-design operation of the Haber-Bosch process. Catalyst poisoning by ppm levels of water and oxygen is considered as the main deactivation mechanism and is evaluated with a microkinetic model. Simulation results show that catalyst activity changes considerably with feed gas composition, even at exceptionally low water contents below 10ppm. A decreased hydrogen content always leads to lower poisoning of the catalyst. It is shown that ammonia offers less flexibility to the operation of Haber-Bosch process under fluctuating hydrogen production compared to nitrogen and argon. Transient and significant changes of catalyst activity are expected in electrolysis coupled Haber-Bosch process.

scholarly journals A Novel Series of Single-Cluster Catalysts: Transition Metal Trimer Clusters Supported on Graphdiyne

2020 ◽  
Author(s):  
Jin-Cheng Liu ◽  
Hai Xiao ◽  
Xiao-Kun Zhao ◽  
Nan-Nan Zhang ◽  
Yuan Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Rational Design ◽  
Heterogeneous Catalysts ◽  
Natural Extension ◽  
Single Atom ◽  
Great Success ◽  
Active Centers ◽  
Heterogenous Catalysis ◽  
Computational Screening ◽  
Single Cluster

<p>While single-atom catalysts (SACs) have achieved great success in the past decade, their application is potentially limited by the simplistic single-atom active centers, which makes single-cluster catalysts (SCCs) a natural extension. SCCs with precise numbers of atoms and structural configurations possess SAC’s merits, yet have greater potentials for catalyzing complex reactions and/or bulky reactants. Through systematic quantum-chemical studies and computational screening, we report here the rational design of transition metal trimer clusters anchored on graphdiyne as a novel kind of stable SCCs with great potentials for efficient and precise heterogenous catalysis. By investigating their structures and catalytic performance for oxygen reduction reaction, hydrogen evolution reaction, and CO<sub>2</sub> reduction reactions, we provide theoretical guidelines for their potential applications as heterogeneous catalysts. These graphdiyne supported SCCs provide an ideal benchmark scaffold for rational design of precise catalysts for industrially important chemical reactions. </p>

scholarly journals High-Throughput Screening Single-Atom Alloy for Electroreduction of Dinitrogen to Ammonia

2021 ◽  
Author(s):  
Guokui Zheng ◽  
Ziqi Tian ◽  
Xingwang Zhang ◽  
Liang Chen ◽  
Xu Qian ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Density Functional ◽  
Ammonia Synthesis ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Single Atom ◽  
Functional Theory ◽  
Metal Doped ◽  
Single Atom Alloy ◽  
Single Atom Alloys

<p></p><p>Exploring electrocatalyst with high activity, selectivity and stability is essential for development of applicable electrocatalytic ammonia synthesis technology. By performing density functional theory calculations, we systematically investigated a series of transition-metal doped Au-based single atom alloys (SAAs) as promising electrocatalysts for nitrogen reduction reaction (NRR). For Au-based electrocatalyst, the first hydrogenation step (*N<sub>2</sub>→*NNH) normally determines the limiting potential of the overall reaction process. Compared with pristine Au(111) surface, introducing single atom can significantly enhance the binding strength of N<sub>2</sub>, leading to decreased energy barrier of the key step, i.e., ΔG(*N<sub>2</sub>→*NNH). According to simulation results, three descriptors were proposed to describe ΔG(*N<sub>2</sub>→*NNH), including ΔG(*NNH), <i>d</i>-band center, and . Eight doped elements (Ti, V, Nb, Ru, Ta, Os, W, and Mo) were initially screened out with limiting potential ranging from -0.75V to -0.30 V. Particularly, Mo- and W-doped systems possess the best activity with limiting potentials of -0.30 V, respectively. Then the intrinsic relationship between structure and the potential performance was further analyzed by using machine-learning. The selectivity, feasibility, stability of these candidates were also evaluated, confirming that SAA containing Mo, Ru ,Ta, and W could be outstanding NRR electrocatalysts. This work not only broadens the understating of SAA application in electrocatalysis, but also devotes to the discovery of novel NRR electrocatalysts.</p><br><p></p>

Boosted electrochemical ammonia synthesis by high-percentage metallic transition metal dichalcogenide quantum dots

Nanoscale ◽  
2020 ◽  
Vol 12 (20) ◽  
pp. 10964-10971 ◽  
Author(s):  
Jian Zhang ◽  
Chongyi Ling ◽  
Wenjie Zang ◽  
Xiaoxia Li ◽  
Shaozhuan Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Transition Metal ◽  
Electrochemical Method ◽  
Ammonia Synthesis ◽  
Value Added ◽  
Transition Metal Dichalcogenide ◽  
Ambient Conditions ◽  
Bosch Process

The electrochemical method can directly convert N2 into the high-value-added NH3 under ambient conditions and is considered to be a green and sustainable alternative to the traditional Haber–Bosch process.

The rational design of single-atom catalysts for electrochemical ammonia synthesis via a descriptor-based approach

2020 ◽  
Vol 8 (33) ◽  
pp. 17078-17088 ◽  
Author(s):  
Jun Long ◽  
Xiaoyan Fu ◽  
Jianping Xiao
Keyword(s):  
Rational Design ◽  
Ammonia Synthesis ◽  
Single Atom

The descriptor-based approach was generalized to the rational design of single-atom catalysts.

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

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...

scholarly journals Ammonia Plasma-Catalytic Synthesis Using Low Melting Point Alloys

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 437 ◽  
Author(s):  
Javishk Shah ◽  
Joshua Harrison ◽  
Maria Carreon
Keyword(s):  
Energy Cost ◽  
Emission Spectroscopy ◽  
Ammonia Synthesis ◽  
Maximum Energy ◽  
Catalytic Synthesis ◽  
Energy Yield ◽  
Ammonia Production ◽  
Inductively Coupled ◽  
Bosch Process ◽  
Scanning Electron

The Haber-Bosch process has been the commercial benchmark process for ammonia synthesis for more than a century. Plasma-catalytic synthesis for ammonia production is theorized to have a great potential for being a greener alternative to the Haber-Bosch process. However, the underlying reactions for ammonia synthesis still require some detailed study especially for radiofrequency plasmas. Herein, the use of inductively coupled radiofrequency plasma for the synthesis of ammonia when employing Ga, In and their alloys as catalysts is presented. The plasma is characterized using emission spectroscopy and the surface of catalysts using Scanning Electron Microscope. A maximum energy yield of 0.31 g-NH3/kWh and energy cost of 196 MJ/mol is achieved with Ga-In (0.6:0.4 and 0.2:0.8) alloy at 50 W plasma power. Granular nodes are observed on the surface of catalysts indicating the formation of the intermediate GaN.

Re-Co alloys and single-atom Re catalysts in ammonia synthesis: A DFT study

2021 ◽  
Vol 513 ◽  
pp. 111801
Author(s):  
Alexander R. Cholach ◽  
Anna A. Bryliakova
Keyword(s):  
Ammonia Synthesis ◽  
Dft Study ◽  
Single Atom ◽  
Co Alloys
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