Analysis of Electroreduction Performance in the N₂-to-NH₃ Reactor with Coupled Kinetics-Mass Transport Modeling

Electrochemical reduction provides a promising and sustainable technology for ammonia synthesis under ambient conditions. At the moment, the majority of research is focused on developing catalysts with high yield and high faradaic efficiency. However, the characteristics of mass transportation and electrokinetics of the reactor are seldom discussed. In this study, a mathematical model was developed that combined mass transportation, charge migration, and electrode kinetics. The model was validated by using experimental data with an average error of 4.7%. With the established theoretical model, the significant physical and chemical phenomena inside the reactor were discussed in detail. Effects of structural and operating parameters including applied potential, N₂ concentration of feed gas, electrolyte concentration, width of the electrolyte channel, thickness of the catalyst layer, and electrolyte flow rate were investigated. The sensitivities of different parameters were further evaluated. It is believed that the work could provide meaningful guidance for the reactor design and scale-up strategy of electrochemical reduction of the N₂-to-NH₃ process.