CAREER: Molecular imprinting strategy to rationally design porous solid acid catalysts for C-C coupling chemistries

催化剂长期以来一直被用于提高化学反应的速度，提高能源效率，并直接反应到所需的产物。沸石是一类纳米多孔固体酸催化剂，特别适合于从天然气和石油中提取的碳氢化合物的反应。近年来，从化石资源到生物可再生原料的转变引发了人们对改性沸石和其他微孔催化剂的兴趣，以提高它们将原料生物质分子反应为高价值燃料和化学品的效率。该项目研究了一种修改酸催化剂的新方法，包括通过在狭窄的空间中限制来提高反应速率，同时促进大块产物分子从活性位点扩散。该方法利用分子印迹原子层沉积方法在活性位点附近创建微孔二氧化硅结构，以诱导约束效应而不施加传输约束。这些具有可调多孔结构的固体酸催化剂将测试其在芳香烷基化和醛醇缩合反应中的有效性和稳定性，选择它们是因为它们在工业化学和升级生物质衍生分子中的广泛应用。该项目将通过将研究成果整合到课堂材料中，为STEM中历史上代表性不足的群体的学生提供研究机会，向当地K-12女学生展示研究者的实验室，以及通过社交媒体渠道为新接触异质催化研究的研究人员制作和播放教育视频，从而将研究与教育紧密结合起来。在过去的二十年中，该领域在理解反应网络、动力学和输运对观察到的速率、选择性和稳定性的影响，以及在密闭空间（如微孔酸性沸石）中发生的化学反应方面取得了重大进展。然而，沸石材料中微孔结构的三维网络通常会引入不希望的传输效应，从而导致不希望的副反应和由孔堵塞引起的催化剂失活。本项目旨在通过开发和实施分子印迹原子层沉积方法，在介孔硅酸铝活性位点附近形成微孔SiO2结构，在不施加输运约束的情况下诱导约束效应，为合理设计多孔材料增加另一个维度。这些具有可调多孔结构的固体酸将通过结合动力学、光谱和理论方法来评估它们在观察速率、选择性和稳定性方面的详细作用。在此过程中，本提案旨在为活性位点操作提供全面的催化剂设计原则，以满足C-C偶联化学的特定要求。该奖项反映了美国国家科学基金会的法定使命，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。

Catalysts have long been used to enhance the rate of chemical reactions, improve energy efficiency, and direct reactions toward desired products. Zeolites are a class of nanoporous solid-acid catalysts that are particularly well suited to reactions of hydrocarbons derived from natural gas and petroleum resources. The transition from fossil-based resources to bio-renewable feedstocks in recent years has triggered interest in modifying zeolites and other microporous catalysts to increase their effectiveness for reacting raw biomass molecules to higher-value fuels and chemicals. The project investigates a novel approach for modifying acid catalysts that involves promoting reaction rates through confinement in tight spaces while facilitating diffusion of bulky product molecules away from the active sites. The approach utilizes a molecular imprinting atomic layer deposition method to create microporous silica structures near the active sites to induce confinement effects without imposing transport constraints. These solid acids catalysts with tunable porous structures will be tested for their effectiveness and stability in aromatic alkylation and aldol condensation reactions, chosen because of their widespread application in industrial chemistry and in upgrading biomass-derived molecules. The project will involve strong coupling between research and education by integrating the research results into classroom materials, providing research opportunities for students from historically underrepresented groups in STEM, showcasing the investigator’s laboratories to local K-12 female students, and creating and broadcasting educational videos via social media channels for researchers who are new to heterogeneous catalysis research.Over the last two decades, the field has made significant progress in understanding the effects of reaction network, kinetics, and transport on observed rates, selectivities, and stabilities, on chemistries occurring on confined spaces such as microporous acidic zeolites. Yet, the three-dimensional network of microporous structures in zeolitic materials often introduces unwanted transport effects that can lead to undesired side reactions and catalyst deactivation caused by pore blockage. This project aims to add another dimension in rationally designing porous materials by developing and implementing molecular imprinting atomic layer deposition methods to create microporous SiO2 architecture near active sites in mesoporous aluminosilicates to induce confinement effects without imposing transport constraints. These solid acids with tunable porous structures will be used to assess their detailed role on observed rates, selectivities, and stabilities by combining kinetic, spectroscopic, and theoretical methods. In doing so, this proposal aims to provide comprehensive catalyst design principles for active site manipulation that match the specific requirements of C-C coupling chemistries.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.