Redox-Mediated Ambient Electrolytic Nitrogen Reduction for Hydrazine and Ammonia Generation

This work presents a redox-mediated electrolytic nitrogen reduction reaction (RM-eNRR) using polyoxometalate (POM) as the electron and proton carrier which frees the TiO2-based catalyst from the electrode and shifts the reduction of nitrogen to a reactor tank. The RM-eNRR process has achieved an ammonium production yield of 25.1 mu g h(-1) or 5.0 mu g h(-1) cm(-2) at an ammonium concentration of 6.7 ppm. With high catalyst loading, 61.0 ppm ammonium was accumulated in the electrolyte upon continuous operation, which is the highest concentration detected for ambient eNRR so far. The mechanism underlying the RM-eNRR was scrutinized both experimentally and computationally to delineate the POM-mediated charge transfer and hydrogenation process of nitrogen molecule on the catalyst. RM-eNRR is expected to provide an implementable solution to overcome the limitations in the conventional eNRR process.

Automated summary

This work introduces a redox-mediated electrolytic nitrogen reduction reaction (RM-eNRR) using POM as an electron and proton carrier, to shift the reduction of nitrogen to a reactor tank. The RM-eNRR process has achieved high ammonium production yield and concentration accumulation, showcasing potential to overcome limitations in conventional eNRR processes. The mechanism underlying RM-eNRR was studied experimentally and computationally, providing insights into the charge transfer and hydrogenation process of nitrogen molecules on the catalyst.