Electrocatalytic Metal-Mediated Nitrogen Fixation

随着世界人口预计在未来35年内从70亿增加到近100亿人，需要开发和商业化新的节能和环境友好的工业过程，这些过程可以提供支持和推进文明所需的化学品。 在这方面，具有百年历史的Haber-Bosch（HB）工艺每年将氮气（N2）和氢气（H2）转化为超过1.4亿公吨的氨（NH3）用作肥料，对我们的生存至关重要，然而，正如实践所示，它目前消耗了世界能源生产的主要部分是氢气，为了提供所需数量的氢气，产生了大量的化学废物。 更重要的是，在分子水平上，科学家们不知道HB过程中的“固氮”是如何工作的。 在这个项目中，Sita博士和他的研究小组正在寻求一种新的化学发展设计，使用电力作为动力和水（H2O）的来源，而不是氢气，以实现廉价，能源和化学高效的固氮的最终目标，不会对自然资源和环境产生巨大的未来影响。在化学部化学催化计划的资助下，马里兰州大学的Sita博士正在寻求开发一种电化学驱动的催化过程，用于将N2转化为NH3的能源效率和原子经济性。 研究活动包括分子离散的单核和双核钼（Mo）配合物的设计和优化，这些配合物可以以导致低温N-N键断裂、N原子官能化和释放含氮产物的方式与N2配位，从而使Mo配合物回到初始起始状态。 本体电解，使用优化的金属电极和三烷基甲硅烷基卤化物，被用来建立一个化学过程，这是催化量的钼络合物，这是生产三烷基甲硅烷基化胺所需的N2。 三烷基甲硅烷基化胺的酸水解提供NH3并使得能够再循环三烷基甲硅烷基卤化物。 验证新提出的实现电催化固氮的范例提供了一个重要的科学基础，可以促进有利于全球文明和世界经济的化学技术的进一步发展。 该项目还在电化学，无机和工业化学，催化和反应机制的跨学科领域培养了多样化的新一代科学家。 Sita博士正在与公众开展外联活动，以促进更好地了解化学及其在支持文明和提高生活质量方面的关键作用。 特别是，Sita博士正在提供K-12级别的STEM教育，特别是通过与代表性不足的群体的学生群体的参与。

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.