Controlling the energy flow in multi-component plasmonic structures for selective catalysis

催化剂是能够激活化学转化的材料。催化剂在选择所需化学产品的同时避免不受欢迎的副反应的能力是一个关键但困难的目标。在这个方向上作出有意义的贡献将对化学催化领域乃至整个化学领域产生重大影响。最近有人提出，在低强度的紫外线-可见光(即来自太阳)的照射下，被称为等离子体金属纳米颗粒的银和金小颗粒可以有效地将能量储存到特定的化学转化中。这与金属上传统的、热驱动的化学反应形成鲜明对比，在这些反应中，能量不分青红皂白地分配给每一种可用的反应。在这个项目中，密歇根大学的Suljo Linic博士正在发展对等离子体催化剂中能量流动的物理性质的理解，以及如何控制这些性质。发展这些洞察力对于有针对性地设计特定化学转化的选择性催化剂至关重要。Linic博士还参与了广泛的教育活动，这些活动以他的研究为基础，促进学生参与科学、技术、工程和数学(STEM)学科。这些活动包括接触来自代表性不足群体的高中生和本科生，以及旨在提高万维网利用率的非常规策略，以接触到学生和公众。在化学系化学催化计划的资助下，Linic博士正在发展对电磁能量如何通过多组分等离子金属纳米结构流动的基本理解。他正在努力实现这样一个概念，即通过设计和控制多金属等离子体纳米结构的光学和电学性质，可以利用光能选择性地激活特定的化学转化。他正在测试一个假设，即这个目标可以通过多组分等离子体纳米结构来实现，该结构具有相对较大的等离子体(银或金)核心(10s为纳米)，旨在收集共振光能，周围环绕着不同材料的薄壳(约1 nm范围)，旨在利用收集到的能量驱动特定的化学转化。他假设这些结构将允许在纳米尺度上完全控制共振能量流，将其高效地转化为所需的化学变化。他采用了一系列表征技术，包括纳米结构几何结构的原子学表征，多组分等离子体材料的电子和光学特性分析，以及振动和反应光谱。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Catalysts are materials that can activate a chemical transformation. The ability of catalysts to select a desired chemical product while avoiding undesired side reactions is a critical, but difficult objective. Making meaningful contributions in this direction would have a large impact on the field of chemical catalysis and across the field of chemistry generally. It was suggested recently that when illuminated with low intensity ultraviolet-visible light (i.e., from the Sun), small particles of silver and gold known as plasmonic metal nanoparticles can efficiently deposit energy into specific chemical transformations. This is in contrast to conventional, thermally-driven chemical reactions on metals where energy is indiscriminately distributed among every available reaction. In this project, Dr. Suljo Linic of the University of Michigan is developing an understanding of which physical properties govern the energy flow in plasmonic catalysts and how to control these properties. Developing these insights is critical for a targeted design of selective catalysts for specific chemical transformations. Dr. Linic is also engaged in a wide range of educational activities that build upon his research to promote engagement of students in science, technology, engineering and mathematics (STEM) disciplines. These activities include reaching out to high school and undergraduate students from underrepresented groups, as well as less conventional strategies aimed at improving the utilization of the World Wide Web in reaching students and the general public.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Linic is developing a fundamental understanding of how electromagnetic energy flows through multicomponent plasmonic metal nanostructures. He is working on realizing the concept that light energy can be used to selectively activate specific chemical transformations by designing and controlling optical and electronic properties of multimetallic plasmonic nanostructures. He is testing the hypothesis that this objective can be accomplished by multicomponent plasmonic nanostructures with a relatively large plasmonic (Ag or Au) core (10s of nm), designed to harvest the resonant light energy, surrounded by a thin shell (~1 nm range) of a different material designed to drive specific chemical transformations using the harvested energy. He postulates that these structures would allow for complete control over the resonant energy flow at the nanoscale, funneling it efficiently into desired chemical transformations. He is employing a slate of characterization techniques including atomistic characterization of the geometric structure of the nanostructures, analysis of electronic and optical properties of the multicomponent plasmonic materials as well as vibrational and reaction spectroscopies.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.