Reducing energy cost of in situ nitrogen fixation in water using an arc-DBD combination

Abstract In this study, a sustainable air plasma-based nitrogen fixation into reactive nitrogen species in water (e.g. nitrate and nitrite) is presented, which mimics the lightning-based nitrogen fixation that occurs in nature. We report a hybrid plasma system that combines a dielectric barrier discharge (DBD) reactor (as an efficient ozone source) and an arc plasma reactor (as an efficient NO x source). This hybrid plasma system completely converts gaseous NO x and O 3 into NO x − in water with almost zero emissions (NO x and O 3 ). Gaseous outlets, in-liquid species, and electrical parameters were investigated. The energy cost for nitrate production via a single-pass reaction was extremely reduced to 8 MJ mol −1 , which enhanced the applicability of the direct one-step nitrogen fixation into NO x − in water for distributed fertilizer production to decrease the dependence on the Haber–Bosh process toward sustainable agricultural development.