Fixation of air nitrogen to ammonia and nitrate using cathodic plasma and anodic plasma in the air plasma electrolysis method

Abstract The fixation of nitrogen (N 2 ) from the air into ammonia (NH 3 ) and nitrate (NO 3 − ) is usually conducted using the Haber–Bosch process, which requires the raw material of hydrocarbons for hydrogen (H 2 ), which has a large amount of energy but produces high CO 2 emissions. An environmentally friendly and energy‐saving alternative is the air plasma electrolysis method, which can be used to synthesize NH 3 and NO 3 − under ambient conditions. In this study, this method was used to inject air into the plasma zone in a K 2 SO 4 electrolyte solution to produce N 2 fixation compounds. The results showed that the use of cathodic plasma promoted the formation of NH 3 but suppressed NO 3 − production. The optimal air injection rate was achieved at 0.6 L.min −1 and an electrical power of 452 W, with a total fixed N 2 of 51.66 mmol. The highest formation of NO 3 − in cathodic plasma was obtained in 35 min, with a value of 29.92 mmol, and 2.57 mmol NH 3 was achieved at 60 min. The high concentration of H 2 gas, which is a by‐product of this process, can contribute to increasing the use of Haber–Bosch green technology in the production of NH 3 .