Ammonia synthesis is responsible for about 30-50% of all energy consumed to produce crops at high yield. About 40% of all crops produced today would not exist without synthetic ammonia. This synthesis, via the state-of-the-art Haber-Bosch ammonia process, requires sensitive catalysts and pressures of several hundred atmospheres. The Haber-Bosch process is highly energy intensive and is estimated to utilize approximately 3% of the world's annual fossil fuels production.
This research addresses catalysis and materials science issues underlying a relatively simple, atmospheric pressure process to convert hydrogen and nitrogen to ammonia. In a first step (nitridation), the target process will activate gaseous dinitrogen from air at atmospheric pressure and elevated temperature by forming a solid metal nitride. Gaseous dinitrogen will be contacted with a metal alloy
particles to achieve this. In a second step hydrogen will react with the activated nitrogen to form ammonia and recover the nitrogen-depleted solids. The process loop is then closed by nitridating the solid again.
Materials with a high nitrogen storage capacity that still readily release nitrogen to form ammonia are needed. Preliminary calculations indicate Mn may be an excellent material for N2 activation at atmospheric pressure and has potential to be developed into an ideal step catalyst by enhancing the ammonia harvest capability. The specific aims are to synthesize and characterize micro to nanoscale particles of Mn and related transition-metal doped alloys that strike a balance between dinitrogen activation/nitrogen storage and ammonia formation. The experimental data will be used to arrive at atom-level models to rationalize the data and direct future work.