沸石分子筛前沿表界面表征和呋喃类转化机理研究

The catalytic carbon conversion has been regarded as one of the most practical solutions to the rapidly growing needs of energy and commodity goods. It includes reactions such as methanol and biomass conversion to platform chemicals like aromatic hydrocarbons. Most of these catalytic processes involve the use of zeolites to some extent. Zeolites have unique microporous structures with inherent but adjustable acidic properties caused by the presence of Brønsted (BAS) and Lewis acid sites (LAS). The surface and catalytic chemistries are however far from simple and have not yet been extensively studied, not to mention the surface molecular structure-activity relationship at an atomistic level. It limits the development of new and more effective catalytic systems. .Our research group have proven capability and expertise in elucidating the surface molecular behaviour and adsorbate-framework interactions in zeolitic materials, by combining conventional and advanced synchrotron X-ray characterisation techniques. More recently, we have also investigated the surface molecular structure-activity relationship in methanol and biomass conversion over zeolite catalysts, offering significant kinetic and mechanistic findings for the science and industrial communities. .Herein, we propose to extend and further the understanding of the surface chemistry in the internal zeolite structures. We plan to first investigate the molecular behaviour of biomass-derived furan molecules in zeolites with different acid-base and spatial properties, followed by a related but systematic study of different transition-metal modified zeolites. Ultimately, by using our specifically designed reactor cell for in-situ synchrotron X-ray powder diffraction measurements, we plan to elucidate the surface molecular structure-activity relationship in the furan conversion reaction in zeolite catalysts. This proposed work will undoubtedly provide a critical understanding of zeolitic materials of academic and practical interest. More importantly, this study will develop a reliable set of toolkits to study the surface chemistry of many microporous materials primarily based on diffraction findings.

在能源与消耗品需求快速增长的时代背景下，碳基和生物质催化转换过程已被视为解决该问题最实际的手段，比如二氧化碳转换成汽油和呋喃类分子转换成芳烃等。分子筛拥有独特的微孔结构和可调节的酸碱性质，被广泛使用在这些转换过程中，然而其表界面化学特性以及构效关系仍有待被深入阐释，阻碍了其在化工和能源等领域中的应用与发展。.本课题组熟知分子筛材料的结构和前沿表界面表征；以同步辐射X射线衍射(SXRD)等主要表征手段，阐释了催化转换过程的构效关系。本课题将进一步加深对分子筛表界面的理解。.我们拟对生物质衍生的呋喃类分子的转换过程进行系统性的研究，深入理解其在分子筛中的表界面化学，分析不同酸碱、金属和空间结构的影响，并通过特别设计的原位SXRD装置，阐释呋喃转换的构效关系。本课题将将提供一套可靠的实验技术，阐明不同微孔材料的表界面化学特性，为分子筛的应用和优化，提供实验层面的支持。

由于能源和商品的可持续发展在各种催化过程中越来越重要，开发具有优越反应性能（转化和产物选择性）的催化剂已成为许多研究人员的核心研究重点之一。该项目主要针对微孔材料的表界面和催化化学开展深入研究，以及在原子水平上对表界面分子级结构-活性关系的揭示。.基于对固态化学和配位化学的理解，我们成功地设计了一系列负载在分子筛微孔中的单原子和纳米团簇催化剂。通过引入多种有机转化反应和模拟酶催化反应作为化学探针，我们系统地对负载型金属催化剂的结构描述符（核数，金属种类和配体类型等）进行了活性评价。在分子筛载体系统中取得的研究经验，激发我们进一步拓展其他微孔材料，如MOFs。利用UiO-66-NH2作为载体，在二级结构构筑单元上组装原子级精确的单原子和纳米团簇。通过利用小分子活化反应的模型反应，如电催化二氧化碳还原反应和光催化甲酸重整反应，微孔负载金属催化剂的结构敏感相关的催化反应活性差异得以体现，这归因于电子和几何结构特性的差异。例如，单原子Cu1、双核Cu2、Cu-Co催化剂的产物分布有明显差异，这归因于活性位点的表面结构、对底物的吸附构型和相关反应能量对反应过程的影响。这项研究提出了一种普适性的方式对一系列原子精确的物种进行性能评价，系统性地对活性位点的结构描述符进行评估和优化，实现高效催化转化。.我们的研究采用了多模态表征方法，对催化剂的电子和几何特性、表界面分子以及吸附物-框架相互作用有了系统的了解。从分子维度深刻地阐述了结构与活性的关联性，提出了催化位点结构描述符的优化策略。这种将传统的催化化学和表界面化学之间交叉融合后所取得的研究成果，将为研究人员继续设计新颖的功能化催化材料提供思路，以应对广泛拓展其应用时面对的长期挑战。