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Monash team publishes Ammonia Economy Roadmap

Earlier this month, Doug MacFarlane and his team of researchers at Monash University published A Roadmap to the Ammonia Economy in the journal Joule. The paper charts an evolution of ammonia synthesis “through multiple generations of technology development and scale-up.” It provides a clear assessment of “the increasingly diverse range of applications of ammonia as a fuel that is emerging,” and concludes with perspectives on the “broader scale sustainability of an ammonia economy,” with emphasis on the Nitrogen Cycle. The Roadmap is brilliant in its simple distillation of complex and competing technology developments across decades. It assesses the sustainability and scalability of three generations of ammonia synthesis technologies. Put simply, Gen1 is blue ammonia, Gen2 is green ammonia, and Gen3 is electrochemical ammonia. It also outlines the amount of research and development required before each could be broadly adopted (“commercial readiness”). The paper thus provides vital clarity on the role that each generation of technology could play in the energy transition, and the timing at which it could make its impact.

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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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A Study on Electrochemical Ammonia Synthesis with Proton-Conducting Solid Oxide Electrolytic Cells

Ammonia has become one of the most important chemicals with its versatility since the Haber-Bosch process was invented. Recently, ammonia has been getting interests because of its possibility as a hydrogen carrier. Since ammonia has high energy density and carbon-free characteristics, using ammonia as a fuel of solid oxide fuel cells is advantageous. However, the Haber-Bosch process spends much electricity because of the high pressure condition, and the process consumes more than 1% of energy consumption worldwide. Therefore, the development of a new method for the ammonia production is necessary. In this study, solid oxide based electrolytic cells were fabricated…

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DFT Analysis of Elementary N2 Electro-Reduction Kinetics on Transition Metal Surfaces

Ammonia is currently produced through the catalytic Haber Bosch process (HB) at temperatures of about 300 to 500 °C and pressure of about 200-300 atm. In a future with plentiful renewable electricity from distributed sources, an electro-chemical system to produce ammonia could efficiently generate ammonia on site and on demand. Possible heterogeneous catalysts for electro-chemical nitrogen reduction are currently marred by the poor rate and selectivity due to difficulty in activating the strong N-N bond and to the competing hydrogen evolution reaction (HER), resulting in infeasible faradaic efficiency. To develop more selective and active catalysts, better understanding of the mechanistic…

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New Insights into Electrocatalysis of Nitrogen Reduction to Ammonia

Ammonia was electrochemically produced from nitrogen and water using a ruthenium–platinum (RuPt) alloy catalyst cathode and a nickel anode at ambient pressure and room temperature. The rate of ammonia formation was 5.1 × 10−9 gNH3 s−1 cm−2 with a 13.2% faradaic efficiency at an applied potential of 0.123 V vs. RHE; it reached 1.08 × 10−8 gNH3 s−1 cm−2 at 0.023 V. Ammonia production was investigated under selected potentials and temperatures. Real-time direct electrochemical mass spectrometric (DEMS) analysis of the evolved gases was performed at various applied potentials. In general, the mass-to-charge ratio signals of hydrogen and ammonia were detected,…

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Enhanced Electrochemical Ammonia Production Via Peptide-Bound Metal

Approximately half of the people on the planet are alive because of synthetically produced ammonia. However, due to the fossil fuels used in the current ammonia synthesis process, its production contributes a significant amount to the world’s greenhouse gas emissions. Haber-Bosch synthesis, which is the most widely used method of producing synthetic ammonia today, requires high temperatures (400-500 °C) and pressures (150-200 atm). This process is also energy intensive, consuming approximately 2% of worldwide energy. By taking an electrochemically-based approach to ammonia synthesis, those harsh conditions and emissions can be eliminated. However, current catalysts are not selective for the desired…

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Highly-Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure

Catalytic conversion of dinitrogen (N2) into ammonia under ambient conditions represents one of the Holy Grails in catalysis and surface science. As a potential alternative to the Haber-Bosch process, electrochemical reduction of N2 to NH3 is attractive owing to its renewability and flexibility, as well as 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 N2 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 NH3…

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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…

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Electrochemical Reduction of Nitrogen to Ammonia over Transition Metals

The ability to produce ammonia in a sustainable and efficient manner has been a topic of scientific and industrial importance for many years. The Haber-Bosch process has acted as the primary process for transforming nitrogen and hydrogen gas into ammonia. This process has become unsustainable in the foreseeable future and requires a cost-effective alternative. Ammonia is a critical component of fertilizer that is vital to the agriculture industry. The electrochemical reduction of N2 to ammonia would eliminate carbon dioxide emissions that are present in current ammonia production processes and allow for a environmentally favorable process. Although the electrochemical reduction of…

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Low-Pressure Electrolytic Ammonia Synthesis Via High-Temperature Polymer-Based Proton Exchange Membrane

The University of North Dakota Energy and Environmental Research Center (EERC) and North Dakota State University (NDSU) have developed a low-pressure electrolytic ammonia (LPEA) production process. The LPEA process uses an electrochemical cell based on an innovative polymer–inorganic composite (PIC) high-temperature (300°C) gas-impermeable proton-exchange membrane conceptualized and partially developed by EERC and NDSU. Because of its operability at ambient pressure and quick start-up capability (versus traditional high-pressure Haber Bosch-based plants), the LPEA process offers compatibility with smaller-scale plants and intermittent operation, and a cost-effective means of monetizing (and storing) renewable energy as ammonia. EERC, NDSU, and Proton OnSite are embarking…