Recent Advances in Electrocatalytic Nitrogen Reduction to Produce Ammonia Under Ambient Conditions

Ammonia (NH3) is one of the most widely used chemicals in industry and agriculture, which is very important to the global economy. At present, the Haber Bosch process is adopted for ammonia synthesis in industry. The experimental temperature and pressure used in this process are relatively high, the process energy consumption is high, the one-way conversion of the hydrogen is low, and a large amount of carbon dioxide is discharged into the atmosphere, causing pollution to the environment. To solve its shortcomings, researchers began a new exploration. Electrocatalytic nitrogen reduction (NRR), as a clean and sustainable method of ammonia synthesis, has attracted extensive attention. However, the low activity and selectivity of electrocatalysts are one of the important challenges. Therefore, the search for cost-effective electrocatalysts has become one of the research hotspots of electrochemical ammonia synthesis. For enhancing the catalytic performance and selective performance of catalysts, scientists have carried out a lot of research on electrochemical nitrogen fixation catalysts. In this review article, electrolytic experimental devices, common ammonia detection research methods, and the electrocatalytic NRR mechanism are summarized, and then the research progress in electrocatalysts (precious metals, transition metals, and non-precious metals) is summarized. Then, the research progress of metal-based electrocatalysts is introduced, and the relevant theoretical calculations are given. The discussion of different catalytic systems provides ideas for the development and improvement of subsequent NRR electrocatalysts.