Imparting Nobility to Base-Metal Hydrides for CO2 Hydrogenation

在这个由化学系化学催化项目资助的项目中，明尼苏达大学双城分校的Connie Lu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。由于其丰富和易于处理，二氧化碳有可能作为化学工业的可再生单碳原料。陆教授正在使用以地球上丰富的金属为特征的催化剂，解决催化领域更广泛的挑战：用更便宜、可用的替代品取代传统的催化金属。除了在催化研究方面积累经验外，研究生还接受培训，以跨越传统学科界限进行合作，并在国外获得与劳动力相关的培训。外展活动的重点是通过实验和/或演示向K-12学生教授催化和能源。正在开发的二氧化碳加氢催化剂的特征是由刘易斯酸性第13族离子支撑的贱金属（Ni，Co和Fe）。所提出的工作的前提是，刘易斯酸性中心将是一个强大的杠杆，以调整在贱金属的反应性。广泛的努力致力于使用合成，光谱和理论方法相结合的机制调查，以评估催化活性如何依赖于支持离子。关键中间体的分离和特征，包括新的阴离子金属氧化物，其负电荷导致高反应性。氢化物转移到其他基板极性C=O基板也进行了研究。该工作建立了关于如何利用刘易斯酸载体的知识，从而赋予碱金属活性位点更高的选择性和/或效率。评估刘易斯酸载体对催化效率和选择性的影响导致催化剂描述，其在性质上是实验的和理论的，其可转移到其它催化剂体系。

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.