Iron Single Atom Catalysts for Electrochemical Ammonia Synthesis: Toward Carbon Free Hydrogen Storage

Abstract Ammonia plays a pivotal role globally, profoundly impacting human activities, especially in agriculture, chemical production, and the textile sector. As the most efficient carbon‐free hydrogen carrier, ammonia is vital for transporting energy over long distances. Haber‐Bosch process producing ammonia from nitrogen accounts for ≈2% of global energy production. Electrochemical conversion offers a sustainable, long‐term solution for ammonia synthesis due to its environmentally friendly characteristics. This approach complements the traditional Haber‐Bosch process, known for its harsh operational conditions and significant CO 2 emissions. Iron (Fe), serving as the active catalytic site in the Haber‐Bosch process and a vital nitrogenase component for biological nitrogen fixation, exhibits superiority over other non‐noble metals in catalyzing ammonia synthesis. Therefore, investigating single‐atom Fe is attracting significant attention for its potential application in electrochemical ammonia synthesis. In this review, the recent advancements in the design and synthesis of single‐atom Fe‐based catalysts for electrochemical ammonia production are summarized. The topic of synthesis and characterization of Fe single‐atom catalysts, as well as their application in the electrochemical reduction of nitrogen and nitrate to ammonia is covered. Additionally, insights are provided into the current challenges and considerations for future directions aimed at designing efficiently Fe single atom‐based catalysts.