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

Mechanistic Insights into Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride Nanoparticles

Ryan Miller November 14, 2019

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 Nitrogen Reduction Reaction on Transition Metal Nitride Nanoparticles in Proton Exchange Membrane Electrolyzers
Paper

Electrochemical Nitrogen Reduction Reaction on Transition Metal Nitride Nanoparticles in Proton Exchange Membrane Electrolyzers

Ryan Miller October 31, 2018

Transition metal nitride nanoparticles are synthesized and utilized as catalysts for electrochemical nitrogen reduction reaction (ENRR) to produce ammonia in a proton exchange membrane electrolyzer (PEMEL). The catalysts show an average ENRR rate and Faradaic efficiency (FE) of 3.3 × 10−10 mol s−1 cm−2 (6.6 × 10−10 mol s−1 mg−1) and 5.95% at −0.1 V within 1 h, respectively. Both the ENRR rate and FE are approximately two orders of magnitude higher than those of noble metal catalysts. Time-dependent results suggest that the catalytic activity of transition metal nitride nanoparticles is stable at −0.1 V, with the catalytic activity decreasing…

Electrochemical Synthesis of Ammonia Using Metal Nitride Catalsyts
Paper

Electrochemical Synthesis of Ammonia Using Metal Nitride Catalsyts

Ryan Miller October 31, 2018

With the development of the Haber process and the subsequent work done by Bosch, ammonia production become an industrially and economically viable way to fix nitrogen. This helped increase the global population and estimates put it at about 40% of the global population’s food comes from ammonia made by the Haber-Bosch process[1]. However, the Haber-Bosch process is an energy intensive process requiring high pressure (15-30 MPa) and relatively high temperature (430 °C – 480 °C) and is highly centralized with only about 13 companies and about 29 plants[2,3]. Renewable energy resources offer a possible alternative way to fix nitrogen at…

Ammonia for Fuel Cells: AFC, SOFC, and PEM
Article

Ammonia for Fuel Cells: AFC, SOFC, and PEM

Ryan Miller October 25, 2018

In the last 12 months ... IHI Corporation tested its 1 kW ammonia-fueled solid oxide fuel cell (SOFC) in Japan; Project Alkammonia concluded its work on cracked-ammonia-fed alkaline fuel cells (AFC) in the EU; the University of Delaware's project for low-temperature

Direct Ammonia Fuel Cell Utilizing an OH- Ion Conducting Membrane Electrolyte
Paper

Direct Ammonia Fuel Cell Utilizing an OH- Ion Conducting Membrane Electrolyte

Ryan Miller November 1, 2017

We describe the techno-economic background and the R&D work scheduled for the ARPA-E project “Direct Ammonia Fuel Cells (DAFCs) for Transportation Applications,” which is about to start under the REFUEL program. The project is led by Shimshon Gottesfeld & Yushan Yan, University of Delaware, Jia Wang & Radoslav Adzic, Brookhaven National Laboratory, Chulsung Bae, Rensselaer Polytechnic Institute, and Bamdad Bahar, Xergy Inc. The multidisciplinary R&D work scheduled will cover the fields of advanced membrane and electrocatalyst development, MEA development and fabrication, and stack engineering. The latter two activities will be supported by work at POCellTech, with Miles Page as lead.…

REFUEL Ammonia Use-Side Funding Awards
Article

REFUEL Ammonia Use-Side Funding Awards

Ryan Miller December 23, 2016

Six of the projects designated for funding by the ARPA-E REFUEL announcement on December 15 involve technologies on the use side of the ammonia energy space. Three focus on generating hydrogen from ammonia. Two focus on fuel cells