Carbon-based nanocomposites for sensing and catalysis

非技术总结：碳基电子纳米复合材料通过启用传感器和改进支撑我们日常生活中使用的材料的工艺，为改善环境提供了新的机会。利用这一潜力需要深入了解这些材料的反应性和新方法，以创建具有新功能的复合材料。化学家对小分子在均匀环境中的溶液中的反应性有很好的理解。 在材料研究部的固态和材料化学计划以及化学部的催化计划的支持下，这项研究旨在将已知的小分子精确度扩展到碳基纳米材料，这些材料具有更复杂的结构和固态组织。将均相反应性概念转化为催化和传感是通过建立将结构附着到碳纳米材料或在碳纳米材料周围组装结构的新方法来实现的。例如，当活性结合金属的材料是组装组合物的一部分时，碳基纳米材料可以负载金属催化剂。马萨诸塞州理工学院的研究人员开发了新的方法，可以按需提供电子，以更有效和更有选择性的过程驱动反应。例如，在催化的许多情况下，需要稀有金属如铂。这在能量转换技术所需的催化剂方面尤其如此。这项研究创造了支持纳米材料，使上级反应与这些有价值的材料的数量少得多。 这一努力还支持教育机会，通过马萨诸塞州理工学院和少数民族服务机构之间的交流计划，使STEM劳动力多样化，并激励新一代科学家从事研究和商业事业。技术总结：在材料研究部门的固态和材料化学计划以及化学部门的催化计划的支持下，这项研究旨在从石墨烯，碳纳米管（CNT），金属纳米颗粒和多孔聚合物中创建多组分功能材料系统。它利用石墨烯表面共价官能化的新方法和多孔聚合物中的封闭空腔来生产具有受控组成的高活性小（5 nm直径）金属纳米颗粒。碳纳米管侧壁的共价修饰被用作将分子催化物种“硬连线”到导电元件并产生高催化活性的方法，并且这种方法将被扩展到产生不对称电催化。在析氧反应中产生的亲电金属-氧代中间体用于与烯烃反应用于电化学环氧化，并且手性CNT-催化剂用于产生光学活性环氧化物。 研究人员共价官能化碳纳米管和涂覆有含有金属结合配体的多孔聚（亚苯基醚）（PAE）的碳纳米管，这使他们能够研究在这种导电载体中Ni（0）对芳基卤化物的还原偶联。开发PAE的新合成方法开辟了可能性的范围，并且可以在聚合物中包含多种金属结合配体。首席研究员和他的团队还研究了含有PAEs的多孔配体是否可以用于仅向每个NP提供单个金属中心，而组合物的其余部分含有一种或多种其他地球丰富的金属。 探索多元素NP组合物以产生用于燃料电池相关反应的催化剂，包括乙醇氧化、氢氧化和氧还原以及新的化学电阻传感器。研究了具有集成染料的多孔PAE作为光氧化还原催化体系，特别是确定不对称PAE口袋是否可以产生手性产物。除了推进基础材料化学和可能产生新的商业相关技术外，该研究还支持教育机会，使劳动力多样化，并激励新一代科学家从事研究和商业职业。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Summary: Carbon-based electronic nanocomposites offer new opportunities to improve the environment by enabling sensors and improving processes that underpin the materials used in our day-to-day existence. Harnessing this potential requires deep understanding of the reactivity of these materials and new methods to create composite materials with novel functionalities. Chemists have a great understanding of the reactivity of small molecules in solution in a homogenous environment. With support from the Solid State and Materials Chemistry program in the Division of Materials Research and the Catalysis program in the Division of Chemistry, this research seeks to extend the known precision of small molecules to carbon-based nanomaterials, which have much more complex structures and solid-state organizations. Translating homogenous reactivity concepts for catalysis and sensing is accomplished by building on new methods for attaching structures to or assembling structures around carbon nanomaterials. For example, carbon-based nanomaterials can support metal catalysts when materials that actively bind the metals are part of the assembled compositions. Researchers at the Massachusetts Institute of Technology develop new methods that deliver electrons on demand to drive reactions in more efficient and selective processes. For example, in many cases in catalysis, rare metals such as platinum are needed. This is particularly true in catalysis needed for energy conversion technologies. This research creates supporting nanomaterials that allow for superior reactivity with much smaller quantities of these valuable materials. This effort also supports educational opportunities to diversify the STEM workforce through an exchange program between Massachusetts Institute of Technology and minority serving institutions, and to inspire new generations of scientists in both research and business careers. Technical Summary: With support from the Solid State and Materials Chemistry program in the Division of Materials Research and the Catalysis program in the Division of Chemistry, this research seeks to create multi-component functional materials systems from graphene, carbon nanotubes (CNTs), metal nanoparticles, and porous polymers. It leverages new methods for the covalent functionalization of graphene surfaces and confined cavities in porous polymers to produce highly active small ( 5 nm diameter) metal nanoparticles of controlled composition. Covalent modification of the sidewalls of carbon nanotubes is used as a method to “hard wire” molecular catalytic species to a conductive element and produce high catalytic activity and this approach will be expanded to the generation of asymmetric electrocatalysis. The electrophilic metal-oxo intermediates generated in the oxygen evolution reaction is used to react with alkenes for electrochemical epoxidation and chiral CNT-catalysts are employed to generate optically active epoxides. The researchers covalently functionalize carbon nanotubes and carbon nanotubes coated with porous poly(phenylene ether)s (PAEs) that contain metal binding ligands, which allows them to investigate reductive coupling of aryl-halides by Ni(0) in such conducting supports. Developing new synthetic methods for PAE opens up the scope of possibilities and a diversity of metal binding ligands can be included in the polymer. The principal investigator and his team also study whether porous ligands containing PAEs could be used to deliver only a single metal center to each NP with the balance of the composition containing one or more other earth abundant metals. Multi-elemental NP compositions are explored to create catalysts for fuel cell relevant reactions, including ethanol oxidation, hydrogen oxidation, and oxygen reduction as well as new chemiresistive sensors. Porous PAEs with integrated dyes are investigated as photoredox catalytic systems, in particular to determine if asymmetric PAE pockets can produce chiral products. In addition to advancing fundamental materials chemistry and potentially producing new commercially relevant technologies, this research also supports educational opportunities to diversify the workforce and inspire new generations of scientists in both research and business careers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.