(506e) Plasma-Based Electrolytic Synthesis of Ammonia from Nitrogen and Water

We present a plasma electrolytic process, characterized by a direct-current, atmospheric-pressure microplasma formed in a flow of nitrogen at the surface of an aqueous, acidic solution, to produce ammonia. Comprehensive statistical analysis of ammonia yield against controls and as a function of various process parameters such as discharge current and solution pH show that the selectivity towards ammonia in terms of faradaic (charge-transfer) efficiency reaches as high as 100%. Scavenger experiments reveal that the reaction mechanism involves solvated electrons and hydrogen radicals which we suggest react preferentially with some nitrogenated species to produce ammonia instead of hydrogen gas under certain conditions. While the power consumption of our process is much larger (~2000 kWh/kg) than Haber-Bosch, the near ambient operation with only electricity and elimination of hydrogen as a feedstock make it suitable for integration with renewable energy sources and promising for distributed production of ammonia.