Work

Coupled NOx production and electrochemical conversion processes for sustainable ammonium synthesis from air

Year: 2025

Type: article

Abstract: Renewable energy-powered decentralized Power-to-X modules can drive the decarbonization of chemical and fuel production, promoting a more sustainable energy landscape. Here, an Air-to-Ammonia system was developed using a commercial dielectric barrier discharge (DBD) plasma-based ozone generator to oxidize air and produce nitrogen oxide intermediaries (NOx/NOx-). A multi-phase electrolyzer then converted NOx/NOx- to NH4+ under ambient conditions, achieving an energy consumption of <100 kWh kgNH4+-1. By optimizing ozone generator parameters, a maximum NOx/NOx- production rate of 166.5 mmol h−1 was obtained. The coupled air oxidation-electrolyzer exhibited a high NH4+ yield of ~1.3 mmol h-1 cm-2 at -2.5 V, which is 5.8 and 3.3 times higher than the electrolyzers with solely gaseous NOx or solely ionic NOx- supply with the same concentrations, respectively. This NOx/NOx- co-supply strategy enables efficient ammonium production from low-concentration NOx sources, contributing to sustainable agriculture and expanding the use of ammonia as a sustainable fuel in remote markets.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2025.168996