Collaborative Research: Operando Three-dimensional Super-resolution Imaging of Catalytic Events in Porous Nanocatalysts

在化学测量和成像计划和化学系催化计划的支持下，格鲁吉亚州立大学的Ning Fang教授和爱荷华州州立大学的Wenyu Huang教授正在开发一种三维超分辨率成像技术，用于在单分子水平上了解纳米孔中的分子运动和反应性。高度可调的核-壳结构具有明确的几何形状和可管理的复杂性的设计和合成，然后可视化的光学成像系统。建议的显微镜的原位3D成像能力，使他们有价值的表征技术的补充，其他传统的方法，如电子显微镜和原子力显微镜。这两个团队还设计了单分子成像实验来研究多步催化反应，其中两个或多个化学转化用纳米级工程多功能催化剂催化，以避免需要分离，纯化和转移每个步骤中产生的中间体。这两个机构的研究生和本科生获得了构建催化纳米结构和开发新的仪器能力以了解单分子水平的分子传输和催化的宝贵技能。亚特兰大和艾姆斯地区的高中生接触到成像，纳米科学和催化的概念，以加强高中的STEM教育。在这项工作中，定义明确的多相催化系统，其中胶体纳米粒子嵌入在核壳介孔二氧化硅材料的对齐通道，开发。单分子轨迹与纳米分辨率获得阐明的影响，孔径，长度，取向，和表面配体上的分子传输和转换。新的实验见解与模型核壳多孔结构获得的纳米级约束的运输可以概括为指导多孔材料的分离和催化的发展。这项研究的长期目标是利用平台催化系统上使用成像技术获得的知识来指导我们未来的催化剂设计，用于广泛的化学转化。

With support from the Chemical Measurement and Imaging Program and the Catalysis Program in the Division of Chemistry, Professor Ning Fang of Georgia State University and Professor Wenyu Huang of Iowa State University are developing a three dimensional super-resolution imaging technique for understanding molecular movement and reactivity in nanopores at the single-molecule level. Highly tunable core-shell structures with well-defined geometry and manageable complexity are designed and synthesized, and then visualized under the optical imaging systems. The in situ 3D imaging capability of the proposed microscopes makes them valuable characterization techniques complementary to other conventional methods, such as electron microscopy and atomic force microscopy. Both teams are also designing single molecule imaging experiments to study multi-step catalytic reactions, in which two or more chemical transformations are catalyzed with a nanoscale-engineered multifunctional catalyst to avoid the need for separation, purification, and transfer of intermediates produced in each step. Graduate and undergraduate students in these two institutions acquire valuable skills in building catalytic nanostructures and in developing new instrumental capabilities to understand molecular transport and catalysis at the single-molecule level. High school students in the Atlanta and Ames area are exposed to the concepts of imaging, nanoscience, and catalysis to enhance STEM education in high schools. In this work well-defined heterogeneous catalytic systems, whereby colloidal nanoparticles are embedded within core-shell mesoporous silica materials of aligned channels, are developed. Single molecule trajectories with nanometer resolution are acquired to elucidate the effects of pore size, length, orientation, and surface ligands on molecular transport and conversion. New experimental insights on transport in nanoscale confinement acquired with the model core-shell porous structures can be generalized to guide the development of porous materials for separation and catalysis. The long-term objective for this research is to use the knowledge acquired using the imaging technique on the platform catalysis system to guide our future catalyst design for a wide range of chemical transformations.