(2ks) Direct Electrosynthesis of Ammonia from Nitrate Reduction Reaction Via Catalyst Design and Electrolyzer Engineering

Research Interests: Electrifying chemical engineering for decarbonization by catalyst, material, and reactor engineering. Research expertise including converting waste nitrogen into ammonia products, water splitting for green hydrogen, and turning carbon dioxide into chemicals and fuels.

Electrochemically converting nitrate ions, a widely distributed nitrogen source in industrial wastewater and polluted groundwater, into ammonia represents a sustainable route for both ammonia fuel synthesis and wastewater treatment. However, the reaction environments in current lab-scale tests are still far from practical conditions for generating ammonia from real wastewater. Here, we first report a high-performance Ru-dispersed Cu nanowire catalyst that delivers an industrial-relevant nitrate reduction current of 1 A cm–2 while maintaining a high NH3 Faradaic efficiency of 93%. This high nitrate-reduction catalytic activity enables over a 99% nitrate conversion into ammonia while still maintaining an over 90% Faradaic efficiency. Next, we design and fabricate a practical membrane electrode assembly (MEA) electrolyzer to perform nitrate reduction reaction. By transferring our catalyst into the MEA electrolyzer, we directly synthesis ammonia from the nitrate-containing influent without the need of additional salt or strong alkaline solution. Overall, we demonstrated an efficient and direct ammonia synthesis via both catalyst design and electrolyzer engineering.