Electrocatalytic Metal-Mediated Nitrogen Fixation

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Electrocatalytic Metal-Mediated Nitrogen FixationAs the world's population is expected to increase from 7 billion to nearly 10 billion people within the next 35 years, there is the need to develop and commercialize new energy-efficient and environmentally-benign industrial processes that can provide chemicals that are required to support and advance civilization. In this regard, the century-old Haber-Bosch (HB) process, which converts nitrogen (N2) and hydrogen (H2) into over 140 million metric tons of ammonia (NH3) to be used as fertilizer each year, is critical for our survival, however, as practiced, it currently consumes up to 5% of the world's energy production and a substantial amount of chemical waste is generated to provide the required amount of hydrogen. More importantly, at the molecular level, scientists do not know how 'nitrogen fixation' by the HB process works. In this project, Dr. Sita and his research group are pursuing a new design for the development of chemistry that uses electricity as the source of power and water (H20) rather than hydrogen for achieving the ultimate goal of inexpensive, energy- and chemically-efficient nitrogen fixation that will not have an enormous future impact on natural resources and the environment. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Sita of the University of Maryland is seeking to develop an electrochemically-driven catalytic process for the energy efficient and atom-economical conversion of N2 into NH3. Research activities include the design and optimization of molecularly-discrete mononuclear and dinuclear molybdenum (Mo) complexes that can coordinate N2 in a manner that leads to low temperature N-N bond cleavage, N-atom functionalization, and release of a nitrogen-containing product in a fashion that recycles the Mo complex back to the initial starting state. Bulk electrolysis, using optimized metal electrodes and trialkylsilyl halides, is being employed to establish a chemical process that is catalytic in the amount of Mo complex that is required for the production of trialkylsilylated amines from N2. Acid hydrolysis of the trialkylsilylated amines is providing NH3 and enabling recycling the trialkylsilyl halide. Validation of the new proposed paradigm for achieving electrocatalytic nitrogen fixation is providing an important scientific foundation that can contribute to the further advancement of chemical technologies that are beneficial to global civilization and the world economy. This project is also training a diverse new generation of scientists in interdisciplinary areas of electrochemistry, inorganic and industrial chemistry, catalysis, and reaction mechanisms. Dr. Sita is engaging in outreach activities with the general public to promote a better understanding of chemistry and its critical role in supporting civilization and a better quality of life. In particular, Dr. Sita is providing STEM education at the K-12 level and especially through involvement with groups of students from underrepresented groups.