Chemical Looping of Manganese to Synthesize Ammonia at Atmospheric Pressure: Sodium as Promoter

Affordable synthetic ammonia (NH3) enables the production of nearly half of the food we eat and is emerging as a renewable energy carrier. Sodium-promoted chemical looping NH(3)synthesis at atmospheric pressure using manganese (Mn) is here demonstrated. The looping process may be advantageous when inexpensive renewable hydrogen from electrolysis is available. Avoiding the high pressure of the Haber-Bosch process by chemical looping using earth-abundant materials may reduce capital cost, facilitate intermittent operation, and allow operation in geographic areas where infrastructure is less sophisticated. At this early stage, the data suggest that 0.28 m(3)of a 50 % porosity solid Mn bed may suffice to produce 100 kg NH(3)per day by chemical looping, with abundant opportunities for improvement.