Recent progress in ammonia production via plasma-electrocatalysis cascade system

Ammonia (NH3) is widely utilized in agriculture to manufacture fertilizers and is an important feedstock in the pharmaceutical, metallurgical, and textile industries. Owing to its highly compressible nature, NH3 is also regarded as an ideal carbon-free hydrogen carrier for the next-generation fuel cells. The Haber-Bosch process is currently the main method for NH3 production but suffers from high energy consumption and intensive carbon emission. Recently, the plasma-electrochemical cascade pathway - plasma nitrogen fixation from air in tandem with electrocatalytic synthesis of NH3 - has emerged as an alternative by the simplified process, low carbon emission, and high NH3 yield. However, the research in this area has not been summarized timely. This review systematically summarizes the research progress of plasma-electrochemical cascade pathway for the first time. Through performance and energy consumption analysis, key issues that need to be addressed have been identified: improving the efficiency of plasma nitrogen fixation and NH3 electrosynthesis. In response to these challenges, corresponding optimization strategies are provided in the end, pointing out the direction for the subsequent research on this emerging field.