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Mechanistic Insights into Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride Nanoparticles

Renewable production of ammonia, a building block for most fertilizers, via the electrochemical nitrogen reduction reaction (ENRR) is desirable; however, a selective electrocatalyst is lacking. Here we show that vanadium nitride (VN) nanoparticles are active, selective, and stable ENRR catalysts. ENRR with 15N2 as the feed produces both 14NH3 and 15NH3, which indicates that the reaction follows a Mars–van Krevelen mechanism. Ex situ and operando characterizations indicate that VN0.7O0.45 is the active phase for ENRR and the conversion of VN0.7O0.45 to the VN phase leads to catalyst deactivation. Quantitative isotopic labeling results identify the amounts of two different types of…

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Electrochemical Reduction of Dinitrogen to Ammonia Using Different Morphologies of Copper As Electro Catalysts

Ammonia is an effective hydrogen storage medium due to ease of transport as liquid, high storage capacity (17.65%) and it can easily be converted to hydrogen by electro-chemical oxidation. Haber-Bosch process is used for the synthesis of ammonia which is energy intensive as it requires high temperature and pressure. It also causes intense carbon emissions as the hydrogen is produced by steam reforming. Alternatively, ammonia can be synthesized electrochemically at ambient conditions from nitrogen and water by employing renewable energy in the presence of an electro catalyst. The major challenge in electrochemical synthesis of ammonia is low Faradaic efficiency. This…

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In Situ Growth of Nitrogen-Doped Carbon Coated γ-Fe; O; Nanoparticles on Carbon Fabric for Electrochemical N; Fixation

Nitrogen fixation to ammonia (NH3) has attracted intensive attention because NH3 is the critical inorganic fertilizers and energy carrier. Haber-Bosch process, the industrial procedure for NH3 production, is confined to the extreme condition requirements. Hence, it is highly desirable to develop a renewable and environment-friendly route for nitrogen fixation to replace the conventional technology. Electrochemical nitrogen reduction reaction (NRR) is one of the most promising techniques since the electrical energy could be produced by synergy with the fast-growing renewable energy. However, electrochemical NRR approach faces huge challenge in breaking extremely high N≡N bond energy (940.95 kJ mol–1) in dinitrogen molecules.…

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Electrochemical Promotion of Ammonia Synthesis with Proton-Conducting Ceramic Fuel Cells -Function of Electrode Interface for Ammonia Formation Reaction-

The advance of efficient and economical energy carrier technology is an important challenge in terms of storage and transport of hydrogen fuels produced from renewable energy. Ammonia is a promising candidate of energy carrier because of high energy density and easy liquefaction as well as a carbon-free fuel.1 Electrochemical synthesis has a potential for an efficient ammonia production in comparison with the industrial Haber–Bosch process. In our previous study, we observed the improvement of electrochemical synthesis of ammonia using iron-based electrode catalyst such as K-Al-Fe-BaCe0.9Y0.1O3 (BCY).2 In the study, basically, H2 decomposition occurs to form protons in the anode side,…

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Energy Storage through Electrochemical Ammonia Synthesis Using Proton-Conducting Ceramics

In this presentation, we provide an overview of an ambitious project to store renewable energy through electrochemical synthesis of ammonia. The joint project between the Colorado School of Mines (Golden, CO) and FuelCell Energy, Inc. (Danbury, CT) is supported through the U.S. Department of Energy ARPA-E ‘REFUEL’ program. The research and development team seeks to harness the unique properties of proton-conducting ceramics to activate chemical and electrochemical reactions for efficient and cost-effective synthesis of ammonia. The system concept is shown in Figure 1; renewable electricity is used to drive electrolysis of the H2O feedstock to form hydrogen. This electrochemically produced…

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Technoeconomic Requirements for Sustainable Ammonia Production

Ammonia, the feedstock for all nitrogen fertilizers, is produced via the Haber-Bosch process, which is responsible for 1-2% of global carbon dioxide emissions each year. An attractive solution to this problem is to create an electrochemical ammonia synthesis process that can produce ammonia using only air, water, and renewable electricity. Researchers across the world have been working toward such a solution for the last several decades, but so far, no economically viable alternative has been created. The Haber-Bosch process is one of the largest-scale, most highly optimized chemical processes in the world; it is very difficult to find a cheaper…

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A Techno-Economic Model for Renewable Ammonia By Electrochemical Synthesis with Proton Conductive Membrane

Ammonia as a renewable liquid fuel has increased global interest for long term energy storage and as a principal chemical candidate in overcoming the challenging practical issues such as storage and transport associated with hydrogen. It is known the Haber-Bosch method of producing ammonia is based on fossil fuels and has a high energy consumption as a result of operating temperatures and pressures of special concern. A techno-economic study is presented for the electrochemical synthesis of ammonia with proton conducting membrane at near ambient pressure. Different coupling pathways were investigated for production of hydrogen and generation of nitrogen to assess…

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Synthesis of Ammonia By RF Non-Thermal Plasma over Ni-MOF-74

Herein, we demonstrate a synergistic approach consisting on radiofrequency plasma to synthesize ammonia in the presence of Ni-MOF-74 as catalyst. The Ni-MOF displayed higher ammonia yields as com-pared to the pure Ni metal. Specifically, ammonia yields as high as 0.23 g-NH3 (kWh-g-catalyst)-1 and energy cost of 265 MJ mol-1 over Ni-MOF were observed. The enhanced catalytic activity of the Ni-MOF in the presence of plasma was attributed to the presence of pores that improved mass transfer of guest and product molecules during reaction, the presence of open Ni metal sites, and lower surface hydrogen re-combination. Furthermore, the ammonia energy yield…

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Electrochemical Synthesis of Ammonia Using Nitrogen and Water in Alkaline Electrolytes Under Ambient Conditions

Sustainable synthesis of Ammonia (NH3) is gaining great attention not only for its use as an alternative renewable energy fuel but also to substitute production of distributed fertilizers through the conventional Haber Bosch process. The conventional Haber-Bosch process to produce NH3 uses fossil fuels in deriving hydrogen from steam reforming of natural gas, is energy intensive and also leads to significant CO2 emission. Alternatively, electrochemical synthesis of ammonia (ESA) through the nitrogen reduction reaction (NRR) in alkaline medium saves the use of hydrogen as a reactant as the aqueous electrolyte forms the source of proton. However, the standard reduction potential…

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Atmonia: Sustainable Ammonia Production Using Electrocatalysis at Ambient Temperature and Pressure

Density functional theory simulations have shed light on reaction mechanisms, rate limiting steps and minimum energy paths for reactions to occur, in vacuum as well as in various media. Using that, we have selected certain criteria and revealed a few metal nitride surfaces that should be efficient and selective catalysts for nitrogen reduction in water. Recently, experimental confirmation was acquired for one of the surfaces. A novel methodology was developed where electrochemical catalysis chamber was directly connected in-line with a flow injection analysis method, providing direct detection of reaction rate and catalyst current efficiency, which is then further confirmed with…