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Presentation

Ammonia Synthesis from Water and Nitrogen Under Ambient Condition Using Single Atom Nickel

Shreya MukherjeeGang Wu

Our dependence on ammonia is not limited to development of fertilizers and other chemicals. Ammonia is being considered an energy vector, capable of being used for energy storage as well as fuel, due to its high energy density, ease of storage and transportation. Growing need for ammonia has forced development of alternate strategies for synthesis worldwide to serve as back up of Haber Bosch. Electrochemical ammonia synthesis is one such alternative. Earlier, we found that, nitrogen vacancy in metal-organic framework-derived disordered carbon is active for nitrogen reduction in alkaline electrolytes. We tried to investigate Fe-N4 sites for nitrogen reduction. It…

Mechanistic Insights into Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride Nanoparticles
Presentation

Mechanistic Insights into Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride Nanoparticles

Xuan YangJared NashShyam KattelJingguang G. ChenYushan YanBingjun Xu

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…

Ammonia Yields during Plasma-Assisted Catalysis Boosted By Hydrogen Sink Effect
Presentation

Ammonia Yields during Plasma-Assisted Catalysis Boosted By Hydrogen Sink Effect

Maria Carreon

Plasma-catalytic ammonia synthesis is known since early 1900s but the possible reaction pathways are currently under investigation. In this article, we present the use of various transition metals and gallium-rich alloys for plasma-catalytic ammonia synthesis. The best three metallic catalysts were identified to be Ni, Sn and Au with the highest ammonia yield of 34%. Furthermore, as compared to its constituent metals some alloys presented about 25-50% better yields. The metals employed were classified in two different categories according to their behavior during ammonia plasma-catalysis. Category I metals are nitrophobic and the measured concentration of Hα in the gas phase…

Effect of Preparation Condition on Ammonia Synthesis over Ru/CeO
Presentation

Effect of Preparation Condition on Ammonia Synthesis over Ru/CeO

Tetsuya NanbaKeisuke KobayashiYuuki NagataJavaid RahatHideyuki Matsumoto

Development of the hydrogen carrier system is of great interest to utilization of renewable energy. To store renewable energy, especially for the electricity from photovoltaic and wind turbine, fluctuation of the generated electricity is not appropriate for the stable supply of the electric power. Also, the hydrogen production by the water electrolysis with the fluctuating electricity results in the fluctuation of hydrogen production. When we store the hydrogen derived from renewable energy in the carrier compounds, it is necessary to consider the reduction or smoothing of fluctuation in the hydrogen flow rate as a feed of chemical process. Although the…

Yittria-Stabilized Zirconia (YSZ) Supports for Low Temperature Ammonia Synthesis
Presentation

Yittria-Stabilized Zirconia (YSZ) Supports for Low Temperature Ammonia Synthesis

Zhenyu ZhangSarah LivingstonLucy FitzgeraldThomas F. FuerstSimona LiguoriJ. Douglas WayColin A. Wolden

NH3 is important as the raw material for fertilizer production and high hydrogen density (17.7 wt. %) energy carrier. Conventionally, NH3 is synthesized through the well-known Haber-Bosch process at 400-500°C and P~150 bar. Both critical reaction conditions and massive production (145 mt NH3 in 2014 globally) make it one of the most energy extensive process, consuming 1-2% of the world’s total energy expense. Here we introduce YSZ as a more active Ru catalyst support than traditionally used supports such as Al2O3. The addition of Cs promoter increased rates an order of magnitude higher by reducing the apparent activation energy from…

Presentation

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

Nishithan C. KaniMeenesh R. Singh

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…

Presentation

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

Yan LiYang Hou

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.…

Presentation

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

Junichiro OtomoChien-I LiKazunori YamamotoHiroki Matsuo

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,…

Presentation

Activation By High Temperature Reduction of Ru Catalyst Supported on Rare Earth Oxide for Ammonia Synthesis

Yuta OguraKatsutoshi NagaokaKatsutoshi Sato

Ammonia is an important chemical feedstock, and more than 80% of the synthesized ammonia is used to produce fertilizer. Ammonia is also being considered as an energy carrier and hydrogen source (1) because it has a high energy density (12.8 GJ m-3) and a high hydrogen content (17.6 wt%), (2) because infrastructure for ammonia storage and transportation is already established, and (3) because carbon dioxide is not emitted when ammonia is decomposed to produce hydrogen. If ammonia could be efficiently produced from a renewable energy source, such as solar or wind energy, problems related to the global energy crisis could…