Collaborative Research: Scalable Production of Metal-Organic Molecular Sieves with Optimized Gas Transport Properties

金属-有机分子筛是一种先进的海绵状材料，在分子尺度上具有内部空穴，具有较大的总孔体积和比表面积。这些分子海绵中精确定义的孔大小和表面开口只允许特定大小的分子通过它们进行运输，这是可调节的。正是金属-有机分子筛的这些独特性质使其在分离、催化、传感器、药物输送和可持续能源技术等领域得到了广泛的应用。目前，这些分子海绵是使用溶液中的沉淀物制成的。这些方法对于广泛的商业用途来说过于昂贵，主要是因为它们不容易扩展。在这里，这项工作的目的是开发一种基于可扩展喷雾干燥技术的新的大规模生产技术，以显著降低制造成本并改善这些材料的运输性能。喷雾干燥技术将允许控制和优化纳米多孔分子海绵的孔径大小和孔结构，以用于此类高级应用。一种新的测量技术将被用来研究微尺度气体在这些材料中的传输。这些研究将指导分子筛的设计，优化分子筛的传输性能。该项目的跨学科性质，跨越材料设计/合成与先进的传输研究相结合，为参与这项工作的高中、本科生和研究生提供了丰富的研究经验。研究工作的主要目标是开发一种先进的可扩展工艺，用于设计构建多功能/多结构纳米多孔杂化金属-有机骨架材料及其复合材料，并展示所需的传输特性。将通过完成以下三个主要目标来实现这一目标：1)通过对气溶胶辅助软化学中涉及的物理化学过程有一个基本的了解，开发气溶胶辅助(即喷雾干燥)软化学作为大规模合成金属-有机骨架的新范例，2)设计和设计具有独特微观结构和功能的MOF粒子，以及3)通过利用最近发展起来的核磁共振技术对微观传输进行详细研究，建立结构和传输特性以及所产生的新材料的相关催化性能之间的关系。这项基础性研究将为合成具有独特微观结构的多功能金属-有机骨架材料及其复合材料提供一套商业可行的设计规则，以优化分子传输和相关催化性能。

Metal-organic molecular sieves are advanced sponge-like materials that possess internal cavities on the molecular scale and exhibit large total pore volume and surface area. The precisely defined pore sizes and surface openings in these molecular sponges only allow molecules of specific size, which is tunable, to be transported through them. It is these unique properties of metal-organic molecular sieves that find their uses in a wide range of applications including separations, catalysis, sensors, drug delivery, and sustainable energy technologies. Currently, these molecular sponges are made using precipitation from a solution. These methods are too expensive for wide commercial uses, primarily because they are not readily scalable. Here, the work aims to develop a new, large-scale production technology based on a scalable spray-drying technique to drastically reduce the fabrication costs and to improve transport properties of these materials. The spray-drying technique will allow controlling and optimizing the pore aperture sizes and pore architecture of nanoporous molecular sponges for such advanced applications. A novel measurement technique will be used to study microscale gas transport in these materials. These studies will be performed to guide the design of molecular sieves optimized with respect to their transport properties. The interdisciplinary nature of the project, spanning material design/synthesis in combination with the advanced transport studies, provide a rich research experience for high school, undergraduate and graduate students involved in the work.The main goal of the researched work is the development of an advanced scalable process for the designed construction of multi-functional/multi-structured nanoporous hybrid metal-organic framework materials and their composites exhibiting the desired transport properties. This goal will be achieved by completing the following three main objectives: 1) to develop aerosol-assisted (i.e., spray-drying) soft chemistry as a new paradigm for the large-scale synthesis of metal-organic frameworks by gaining a fundamental understanding of physico-chemical processes involved in aerosol-assisted soft chemistry, 2) to design and engineer MOF particles with unique microstructures and functionalities, and 3) to establish the relationship between structural and transport properties as well as the related catalytic performance of the resulting new materials through detailed studies of microscopic transport by a recently developed nuclear magnetic resonance technique. This fundamental research will lead to a set of design rules for the commercially-viable synthesis of multi-functional metal-organic framework materials and their composites with unique microstructures optimized for molecular transport and related catalytic performance.