Scalable synthesis of MoS2 nanosheets electrocatalyst towards high-efficiency nitrite reduction to ammonia

Ammonia is a vital chemical raw material for both industry and agriculture, the current ammonia synthesis process is based on the Haber-Bosch process yet faces issues of high-energy consumption and high CO2 emission. Electrochemical nitrite reduction reaction (NO2-RR) has been considered as one of the alternative paths for ammonia synthesis. Here, we develop a large-scale viable route for synthesis of 2H-MoS2 nanosheets (MoS2 NSs), which show high activity as electrocatalyst for high-efficiency conversion of NO2- RR to ammonia, the yields of NH3 production rate reaches as high as 8.99 mg cm-2 h-1 with a faradaic efficiency of 93.52%. A hybrid electrolytic cell is constructed by coupling MoS2 NSs as NO2-RR cathode in neutral electrolyte with oxygen evolution reaction (OER) in alkaline solution, which can operate stably for more than 120 h with the capability of continuously producing ammonia at the production rate of 38.79 mg cm-2 h-1.

Automated summary

Ammonia is an important chemical raw material, but the current synthesis process suffers from high energy consumption and CO2 emission. The electrochemical nitrite reduction reaction (NO2-RR) offers an alternative path for ammonia synthesis. This study presents a large-scale route for synthesizing 2H-MoS2 nanosheets (MoS2 NSs) as electrocatalysts for efficient conversion of NO2-RR to ammonia, achieving a high ammonia production rate of 8.99 mg cm-2 h-1 with a faradaic efficiency of 93.52%. A hybrid electrolytic cell is constructed using MoS2 NSs as the NO2-RR cathode and oxygen evolution reaction (OER) in alkaline solution, enabling continuous and stable ammonia production at a rate of 38.79 mg cm-2 h-1 for over 120 hours.