Alternatives to Ammonia Synthesis: An Electrochemical Haber-Bosch Process

Several alternatives to the existing process for ammonia synthesis, the Haber-Bosch Process, have been proposed in the past two decades, including the electrochemical synthesis in aqueous, molten salt or solid electrolyte cells. The present work reviews results of recent efforts (last 3 years) for the electrochemical synthesis of ammonia. An Electrochemical Haber-Bosch Process is also demonstrated. The proposed BaZrO3 – based protonic ceramic membrane reactor combines hydrogen production via the reactions of methane steam reforming and water-gas shift at the anode (Ni-composite) with ammonia synthesis from N 2 and protons (H + ) at the cathode (VN-Fe). Hydrogen extraction from…


Electrification of Ammonia Synthesis

Near-term prospects for decarbonized ammonia synthesis rely on conventional thermochemical Haber Bosch coupled to either electrochemical hydrogen production or methods of mitigating carbon emissions, such as carbon capture and storage. Thermochemical Haber Bosch requires high temperatures to achieve significant rates of ammonia synthesis and high pressures in order to achieve reasonable conversions of nitrogen and hydrogen to ammonia. Next-generation electrically-driven routes raise the prospect of using voltage in the place of temperature and pressure – an ambient pressure and room temperature route through which renewable electricity can be used to convert nitrogen and hydrogen to ammonia. Electrically-driven routes for nitrogen…


Whither Aqueous Electro-reduction of Nitrogen to Ammonia?

Electrochemical reduction of N 2 (NRR) is widely recognised as an alternative to the traditional Haber-Bosch production process for ammonia. The high-energy efficiency, low-cost variant of this process involves an aqueous electrolyte and there is now a substantial literature on this topic. However, though the challenges of NRR experiments have become better understood, the reported rates in these aqueous solution studies are often too low to be convincing that reduction of the highly unreactive N 2 molecule has actually been achieved. Unfortunately, there are many possible impurity sources that can interfere with robust measurements. In this presentation we will discuss…


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.


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…


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…


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.…


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,…


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…


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…