Liquid surface discharge nitrogen fixation: performance, spatial distribution and mechanisms

Abstract Gas–liquid discharge is considered to be one of the most promising technologies for nitrogen fixation because of its ability to generate high concentrations of reactive species in the gas–liquid phase. Increasing the contact area between the plasma and the liquid is considered to be an effective method to improve the mass transfer efficiency. In this study, a nanosecond pulse was employed to drive a coplanar plate-like electrode to achieve a large liquid surface discharge of about 70 * 30 mm 2 , the effects of voltage, frequency, conductivity and temperature on NO x − concentration in water were investigated and the nitrogen fixation performance and plasma characteristics were qualitatively analyzed at different discharge positions. The results show that both electrical and solution parameters have important effects on the nitrogen fixation performance of liquid surface discharges. The highest NO 3 − concentration was up to 1.43 mM and the lowest energy consumption for nitrogen fixation was 14.74 MJ mol −1 . The dissolution of gas-phase nitrogen oxides is the key to the formation of liquid-phase nitrogen oxides, and higher vibration and gas temperatures are favorable for NO x − generation. This study provides some theoretical ideas for the design of gas–liquid discharge reactors.