scholarly journals Interfacial engineering of cobalt sulfide/graphene hybrids for highly efficient ammonia electrosynthesis

2019 ◽  
Vol 116 (14) ◽  
pp. 6635-6640 ◽  
Author(s):  
Pengzuo Chen ◽  
Nan Zhang ◽  
Sibo Wang ◽  
Tianpei Zhou ◽  
Yun Tong ◽  
...  
Keyword(s):  
Metal Sulfide ◽  
Reduction Reaction ◽  
Cobalt Sulfide ◽  
Ambient Conditions ◽  
Transport Channel ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Strongly Coupled ◽  
Interfacial Engineering ◽  
Highly Efficient

Electrocatalytic N2reduction reaction (NRR) into ammonia (NH3), especially if driven by renewable energy, represents a potentially clean and sustainable strategy for replacing traditional Haber–Bosch process and dealing with climate change effect. However, electrocatalytic NRR process under ambient conditions often suffers from low Faradaic efficiency and high overpotential. Developing newly regulative methods for highly efficient NRR electrocatalysts is of great significance for NH3synthesis. Here, we propose an interfacial engineering strategy for designing a class of strongly coupled hybrid materials as highly active electrocatalysts for catalytic N2fixation. X-ray absorption near-edge spectroscopy (XANES) spectra confirm the successful construction of strong bridging bonds (Co–N/S–C) at the interface between CoSxnanoparticles and NS-G (nitrogen- and sulfur-doped reduced graphene). These bridging bonds can accelerate the reaction kinetics by acting as an electron transport channel, enabling electrocatalytic NRR at a low overpotential. As expected, CoS2/NS-G hybrids show superior NRR activity with a high NH3Faradaic efficiency of 25.9% at −0.05 V versus reversible hydrogen electrode (RHE). Moreover, this strategy is general and can be extended to a series of other strongly coupled metal sulfide hybrids. This work provides an approach to design advanced materials for ammonia production.

Highly efficient electrochemical ammonia synthesis via nitrogen reduction reactions on a VN nanowire array under ambient conditions

2018 ◽  
Vol 54 (42) ◽  
pp. 5323-5325 ◽  
Author(s):  
Xiaoping Zhang ◽  
Rong-Mei Kong ◽  
Huitong Du ◽  
Lian Xia ◽  
Fengli Qu
Keyword(s):  
High Performance ◽  
Ammonia Synthesis ◽  
Nanowire Array ◽  
Reduction Reaction ◽  
Carbon Cloth ◽  
Ambient Conditions ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction ◽  
Highly Efficient ◽  
High Ammonia

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.

scholarly journals Transition Metal Aluminum Boride as a New Candidate for Ambient-Condition Electrochemical Ammonia Synthesis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yang Fu ◽  
Peter Richardson ◽  
Kangkang Li ◽  
Hai Yu ◽  
Bing Yu ◽  
...  
Keyword(s):  
Transition Metal ◽  
High Energy ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Applied Potential ◽  
Ambient Conditions ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Aluminum Boride ◽  
Metal Aluminum

AbstractAchieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber–Bosch process. Unfortunately, the electrochemical N2 reduction reaction (NRR) method as a rising approach currently still shows low selectivity (Faradaic efficiency < 10%) and high-energy consumption [applied potential at least − 0.2 V versus the reversible hydrogen electrode (RHE)]. Here, the role of molybdenum aluminum boride single crystals, belonging to a family of ternary transition metal aluminum borides known as MAB phases, is reported for the electrochemical NRR for the first time, at a low applied potential (− 0.05 V versus RHE) under ambient conditions and in alkaline media. Due to the unique nano-laminated crystal structure of the MAB phase, these inexpensive materials have been found to exhibit excellent electrocatalytic performances (NH3 yield: 9.2 µg h−1 cm−2 mg cat. −1 , Faradaic efficiency: 30.1%) at the low overpotential, and to display a high chemical stability and sustained catalytic performance. In conjunction, further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals, while Mo exhibits specific catalytic activity toward the subsequent reduction reaction. Overall, the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance. The significance of this work is to provide a promising candidate in the future synthesis of ammonia.

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

2020 ◽  
Vol 12 (1) ◽  
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.

Enhancing electrocatalytic N2 conversion to NH3 by MnO2 ultralong nanowires with oxygen vacancies

2021 ◽  
Vol 02 ◽  
Author(s):  
Guangbin Wang ◽  
Renna Zhao ◽  
Fahao Ma ◽  
Zeyan Wang ◽  
Peng Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Manganese Oxides ◽  
Oxygen Vacancies ◽  
High Energy ◽  
Reduction Reaction ◽  
Ambient Conditions ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Vacancy Defects ◽  
One Step

Background: At present, industrial synthesis of NH3 mainly relies on the Haber-Bosch process, which is characterized by harsh reaction conditions and high energy consumption. Electrochemical nitrogen reduction is considered to be a mild and sustainable alternative method for producing NH3, but efficient electrocatalyst under ambient conditions is the prerequisite for NH3 production. Objective: To demonstrate that CP@MnO2 ultralong nanowires is a highly-efficient electrocatalyst for N2 reduction reaction (NRR) under ambient conditions. Methods: The α-phase MnO2 synthesized by one-step hydrothermal method has an ultralong nanowires structure and oxygen vacancy defects. The catalysts was characterized by XRD, TEM, XPS, etc. The produced NH3 was estimated by indophenol blue method by UV-vis absorption spectra. Results: Such catalyst attains high Faradaic efficiency (FE) of 8.8% and a large NH3 yield of 1.13×10−10 mol cm−2 s−−1 at −0.7 V versus reversible hydrogen electrode in 0.1 M Na2SO4. In addition, the catalyst also shows high electrochemical stability and selectivity for NH3 formation. Conclusion: MnO2 ultralong nanowires can expose higher density of active sites and the spontaneously formed oxygen vacancies can manipulate the electronic structure of manganese oxides and provide coordination unsaturation sites (CUS) to enhance the adsorption of N2, which is the main reason for the high activity of the catalyst.

scholarly journals Communication—Partial Oxidation of MnS for Synergistic Electrocatalysis of N2-to-NH3 Fixation at Ambient Conditions

2021 ◽  
Author(s):  
Peiei Li ◽  
Dan Cheng ◽  
Xiaohua Zhu ◽  
Meiling Liu ◽  
Youyu Zhang
Keyword(s):  
Partial Oxidation ◽  
Reduction Reaction ◽  
Ambient Conditions ◽  
Faradaic Efficiency ◽  
Bosch Process ◽  
Ambient Nh3 ◽  
Reaction Performance ◽  
Excellent Selectivity

Abstract Compared with the traditional Haber-Bosch process, electrochemical N2-to-NH3 reduction affords an eco-friendly and sustainable alternative to ambient NH3 synthesis with the aid of efficient electrocatalysts. In this work, partial oxidation of MnS to obtain the MnS-Mn3O4 is proved as a promising noble-free electrocatalysts of N2to NH3 fixation at ambient conditions. When tested in 0.1 M Na2SO4, the electrochemical N2 reduction reaction performance of MnS-Mn3O4 is improved comparing with the MnS, which achieves large NH3 yield of 16.74 μg h–1 mgcat.–1 and a high Faradaic efficiency of 5.72%. It also exhibits excellent selectivity of N2-to-NH3 and strong long-term electrochemical stabil

scholarly journals A Pd/MnO2 Electrocatalyst for Nitrogen Reduction to Ammonia under Ambient Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 802
Author(s):  
Chang Sun ◽  
Yingxin Mu ◽  
Yuxin Wang
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Pd Nanoparticles ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Supported Pd

Electrochemical ammonia synthesis, which is an alternative approach to the Haber–Bosch process, has attracted the attention of researchers because of its advantages including mild working conditions, environmental protection, and simple process. However, the biggest problem in this field is the lack of high-performance catalysts. Here, we report high-efficiency electroreduction of N2 to NH3 on γ-MnO2-supported Pd nanoparticles (Pd/γ-MnO2) under ambient conditions, which exhibits excellent catalytic activity with an NH3 yield rate of 19.72 μg·mg−1Pd h−1 and a Faradaic efficiency of 8.4% at −0.05 V vs. the reversible hydrogen electrode (RHE). X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization shows that Pd nanoparticles are homogeneously dispersed on the γ-MnO2. Pd/γ-MnO2 outperforms other catalysts including Pd/C and γ-MnO2 because of its synergistic catalytic effect between Pd and Mn.

scholarly journals The Synthesis of V2O3 Nanorings by Hydrothermal Process as an Efficient Electrocatalyst Toward N2 Fixation to NH3

2020 ◽  
Vol 8 ◽  
Author(s):  
Ning Wang ◽  
Qing-Song Song ◽  
Wen-Jing Liu ◽  
Jian Zhang
Keyword(s):  
Noble Metal ◽  
Hydrothermal Process ◽  
Maximum Yield ◽  
Reduction Reaction ◽  
Reversible Hydrogen Electrode ◽  
Proof Of Concept ◽  
Ambient Conditions ◽  
Hydrogen Electrode ◽  
Etching Mechanism ◽  
Template Free

A new ringlike V2O3 architecture was successfully synthesized by a template-free hydrothermal method, and the sulfur ions-assisted central-etching mechanism of the ringlike structure was proposed. Herein, as a proof-of-concept experiment, taking V2O3 nanorings as non-noble-metal-free nitrogen reduction reaction (NRR) catalysts, they show desired electrocatalytic performance toward NRR under ambient conditions (maximum yield: 47.2 µg h−1 mgcat.−1 at −0.6 V vs. reversible hydrogen electrode, maximum Faraday efficiency: 12.5% at −0.5 V vs. reversible hydrogen electrode), which is significantly higher than those of noble metal-based catalysts.

An ultrasmall Ru2P nanoparticles–reduced graphene oxide hybrid: an efficient electrocatalyst for NH3 synthesis under ambient conditions

2020 ◽  
Vol 8 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Runbo Zhao ◽  
Chuangwei Liu ◽  
Xiaoxue Zhang ◽  
Xiaojuan Zhu ◽  
Peipei Wei ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reversible Hydrogen Electrode ◽  
Ambient Conditions ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Reduced Graphene

A Ru2P–reduced graphene oxide hybrid acts as a superior catalyst for electrochemical N2 fixation in 0.1 M HCl, achieving a large NH3 yield of 32.8 μg h−1mgcat.−1 and a high faradaic efficiency of 13.04%−0.05 V vs. the reversible hydrogen electrode.

scholarly journals Boosting Electrochemical Nitrogen Reduction Performance over Binuclear Mo Atoms on N-Doped Nanoporous Graphene: A Theoretical Investigation

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1777 ◽  
Author(s):  
Ruijie Guo ◽  
Min Hu ◽  
Weiqing Zhang ◽  
Jia He
Keyword(s):  
Free Energy ◽  
Binding Free Energy ◽  
Product Yield ◽  
Reduction Reaction ◽  
Ambient Conditions ◽  
Present Contribution ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction ◽  
Mo Catalyst ◽  
Nanoporous Graphene

Exploration of efficient catalysts is a priority for the electrochemical nitrogen reduction reaction (NRR) in order to receive a high product yield rate and faradaic efficiency of NH3, under ambient conditions. In the present contribution, the binding free energy of N2, NNH, and NH2 were used as descriptors to screen the potential NRR electrocatalyst among different single or binuclear transition metal atoms on N-doped nanoporous graphene. Results showed that the binuclear Mo catalyst might exhibit the highest catalytic activity. Further free energy profiles confirmed that binuclear Mo catalysts possess the lowest potential determining step (hydrogenation of NH2* to NH3). The improved activities could be ascribed to a down-shift of the density of states for Mo atoms. This investigation could contribute to the design of a highly active NRR electrocatalyst.

scholarly journals Mechanistic Insight into High Yield Electrochemical Nitrogen Reduction to Ammonia using Lithium Ions

2019 ◽  
Author(s):  
Anku Guha ◽  
Sreekanth Narayanru ◽  
Nisheal M. Kaley ◽  
D. Krishna Rao ◽  
Jagannath Mondal ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Reduction Reaction ◽  
High Yield ◽  
Ambient Conditions ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction ◽  
Mechanistic Insight ◽  
Working Electrode ◽  
Hydrogen Carrier ◽  
Scientific Attention

<p>Development of methods for economically feasible greener ammonia (NH<sub>3</sub>) production is gaining tremendous scientific attention. NH<sub>3</sub> has its importance in fertilizer industry and it is envisaged as a safer liquid hydrogen carrier for futuristic energy resources. Here, an aqueous electrolysis based NH<sub>3</sub> production in ambient conditions is reported, which yields high faradaic efficiency (~12%) NH<sub>3 </sub><i>via</i> nitrogen reduction reaction (NRR) at lower over potentials (~ -0.6V <i>vs.</i> RHE or -1.1V <i>vs.</i> Ag/AgCl). Polycrystalline copper (Cu) and gold (Au) are used as electrodes for electrochemical NRR, where the electrolyte which yields high amount of NH<sub>3 </sub>(~41 µmol/L) is 5M LiClO<sub>4</sub> in water with Cu as working electrode. A detailed study conducted here establishes the role of Li<sup>+</sup> in stabilizing nitrogen near to the working electrode - augmenting the NRR in comparison to its competitor - hydrogen evolution reaction, and a mechanistic insight in to the phenomenon is provided. <sup>15</sup>N<sub>2</sub> assisted labeling experiments are also conducted to confirm the formation of ammonia <i>via</i> NRR. This study opens up the possibilities of developing economically feasible electrodes for electrochemical NRR at lower energies with only transient modifications of electrodes during the electrolysis, unlike the studies reported on complex electrodes or electrolytes designed for NRR in aqueous medium to suppress the hydrogen generation. </p>

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