Highly Efficient Ammonia Synthesis by Gas–Liquid Interface Pulsed Discharge Plasma: A Synthesis Method without Hydrogen

In order to replace the traditional high-energy synthetic ammonia method, new synthetic ammonia technologies and methods are developing day by day. In this investigation, a gas–liquid interface pulsed discharge plasma technology is proposed, which uses only nitrogen and pure water to synthesize ammonia efficiently at room temperature and atmospheric pressure without injecting hydrogen gas and catalyst. The effects of the reactor structure, gas flow rate, and pulse power parameters on the synthesis of ammonia were studied experimentally, and the parameters were optimized. The results show that under the optimum conditions of the electrode distance gas–liquid ratio 10:4 and the discharge time 5 min, the maximum ammonia production was 7.67 mg/h and the energy consumption is 0.68 g/kW h, but the selectivity was highest when the electrode space gas–liquid ratio was 10:7. In addition, radicals and active substances in the reaction process were measured and analyzed by emission spectroscopy and chemical analysis. The transient behavior of ammonia production and the mechanism of ammonia formation were studied. The application of this method provides a new technical direction for improving the rate of ammonia synthesis and for research of sustainable nitrogen fixation.