Imparting Nobility to Base-Metal Hydrides for CO2 Hydrogenation

在这项由化学系化学催化计划资助的项目中，明尼苏达大学的康妮·卢教授正在开发分子催化剂，将二氧化碳转化为有用的化学品和/或液体燃料。生产商品化学品和储存能源的可持续进程与安全的能源未来日益相关。由于二氧化碳的丰富和易于处理，它有可能成为化学工业的一种可再生的单一碳原料。卢教授正在使用以富含稀土金属为特色的催化剂，以应对催化领域的一个更广泛的挑战：用更便宜、可获得的替代品取代传统的催化金属。除了积累催化研究方面的经验外，研究生还接受了跨越传统学科边界进行协作的培训，并在国外获得了与劳动力相关的培训。推广活动的重点是通过实验和/或演示向K-12学生教授催化和能量。正在开发的用于二氧化碳加氢的双金属催化剂具有由Lewis酸性基团13离子支撑的贱金属(Ni、Co和Fe)。这项拟议工作的前提是，刘易斯酸性中心将成为调节贱金属反应性的强大杠杆。大量的工作致力于机械研究，使用合成、光谱和理论方法相结合的方法来评估催化活性如何依赖于支撑离子。分离和表征了关键的中间体，包括新型阴离子金属氢化物，其负电荷导致了高反应活性。还研究了氢化物向具有极性C=O衬底的其他衬底的转移。这项工作建立了关于如何利用Lewis酸载体的知识，从而赋予贱金属活性中心更高的选择性和/或效率。评估Lewis酸载体对催化效率和选择性的影响导致对催化剂的描述，包括实验和理论上的描述，这些描述可能会转移到其他催化剂系统。

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Connie Lu of the University of Minnesota, Twin Cities is developing molecular catalysts to transform carbon dioxide into useful chemicals and/or liquid fuels. Sustainable processes for producing commodity chemicals and for storing energy are increasingly relevant to a secure energy future. Because of its abundance and ease of handling, carbon dioxide has the potential to serve as a renewable single-carbon feedstock for the chemical industry. Professor Lu is using catalysts featuring earth-abundant metals addressing a broader challenge in catalysis: to replace traditional catalytic metals with cheaper, available alternatives. Besides building experience in catalysis research, graduate students are trained to collaborate across traditional disciplinary boundaries and gain workforce-related training abroad. Outreach activities focus on teaching catalysis and energy to K-12 students through experiments and/or demonstrations.The bimetallic catalysts being developed for carbon dioxide hydrogenation feature base metals (Ni, Co, and Fe) supported by Lewis acidic Group 13 ions. The premise of the proposed work is that the Lewis acidic center will be a powerful lever to tune the reactivity at the base metal. Extensive effort is dedicated to mechanistic investigations using a combination of synthetic, spectroscopic, and theoretical approaches to evaluate how catalytic activity depend on the supporting ion. Key intermediates are isolated and characterized, including novel anionic metal hydrides, whose negative charges result in high reactivity. Hydride transfer to other substrates with polar C=O substrates is also investigated. The work builds knowledge about how to leverage Lewis acid supports, so to endow higher selectivity and/or efficiency to base-metal active sites. Assessing the impact of the Lewis acid support on catalytic efficiency and selectivity leads to catalyst descriptions, both experimental and theoretical in nature, which may be transferrable to other catalyst systems.