Electrocatalytic Metal-Mediated Nitrogen Fixation

电催化金属介导的固氮随着世界人口预计在未来35年内从70亿增加到近100亿，有必要开发新的节能和环境友好的工业过程，并将其商业化，这些过程可以提供支持和推进文明所需的化学物质。在这方面，已有百年历史的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，这对我们的生存至关重要，但实际上，它目前消耗了世界能源产量的5%，并产生了大量化学废物来提供所需的氢气。更重要的是，在分子水平上，科学家们并不知道HB过程的固氮作用是如何发挥作用的。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开发设计，使用电力和水(H20)而不是氢气作为动力和水的来源，以实现廉价、能源和化学效率高的固氮的最终目标，而不会对自然资源和环境产生巨大的未来影响。在化学系化学催化项目的资助下，马里兰大学的西塔博士正在寻求开发一种电化学驱动的催化过程，用于将氮气转化为氨，从而实现能源效率和原子经济性。研究活动包括设计和优化分子离散的单核和双核钼(Mo)络合物，这种络合物可以与氮配位，导致低温N-N键断裂，N原子官能化，以及以将钼络合物循环回到初始起始状态的方式释放含氮产品。使用优化的金属电极和三烷基硅基卤化物的本体电解被用来建立一种化学过程，该化学过程具有催化作用，其量是从氮气生产三烷基硅化胺所需的钼络合物。三烷基硅化胺的酸解提供了NH3，并能够回收三烷基硅基卤化物。为实现电催化固氮而提出的新范式的验证正在为进一步发展有益于全球文明和世界经济的化学技术提供重要的科学基础。该项目还在培养电化学、无机和工业化学、催化和反应机理等跨学科领域的不同的新一代科学家。Sita博士正在与公众进行外联活动，以促进对化学及其在支持文明和更好的生活质量方面的关键作用的更好了解。特别是，Sita博士正在提供K-12级别的STEM教育，特别是通过参与代表人数不足的群体的学生团体。

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.