杂原子掺杂的孔道结构调变的单分散介孔纳米碳球的可控制备及其酸碱双功能协同催化反应性能的研究

Carbon nano-porous materials in the field of heterogeneous catalysis show good prospects for the application, but in the large-scale preparation（kg scale)，modulation of the pore structure (pore diameter> 3.0 nm), miscellaneous atoms doping and surface functionalization regulation, there are still a lot of scientific challenges. In this proposal, inspired by the understanding on the formation mechanism of monodisperse mesoporous silica nanoparticles (MSNs) proposed by us, ie., Controllable Weak/Strong Self-Asssmbling Interaction (CWSSAI) mechanics,the mesoporous carbon nanomaterials (MCNs) with controlled uniform particle size (particle size <200 nm), and tunable mesoporous nanostructure will be synthesized based on the soft- and hard-templating strategies. Subsequently, N/S heteroatoms are incorporated into the channel surface of MCNs by a combined technique of doping and post-synthesis modification via sequential multistep. By immobilizing both acidic (-SO3H) and basic (N as Lewis base is present in the C-N hybrid form)centers onto the surface of MCNs with spatial proximity between each other in a precisely controllable way, these incompatible groups can coexist and catalyze C-C coupling reaction as enzyme in a synergetic mode. The structure and acid-base properties of dual-functional catalysts were studied by various characterization means. The influence of acid-base type, the matching and spatial distribution between acid and base, and surface hydrophilicity-hyfeophobicity of confined nanospace on the cooperative catalysis have been investigated. Thus, the systematic and in-depth exploration on the control of the microstructure of the active sites in the confined nanopores has become an urgent necessity, as understanding this behavior is essential to designing superior multifunctional catalysts. We believe that our studies can not only broaden the types of carbon-based nanoporous materials but also strength the understanding of the basic theory of Structure- Reactivity of the carbon-based cooperative catalysts.

碳纳米多孔材料在多相催化领域展现出了很好的应用前景, 但在介孔纳米碳球（颗粒尺寸<200 nm）的规模化制备（公斤级）、孔道结构调变（孔径>3.0 nm）、杂原子掺杂以及表面功能化调控方面仍存在很多科学挑战。本课题借鉴我们最新发展的“可控强弱自组装相互作用”机制合成介孔SiO2纳米球的策略，拟采用软/硬模板结合的合成策略，实现孔道结构调变的高度单分散介孔纳米碳球的宏量化制备，并以其为载体利用“掺杂和后合成改性的组合功能化”技术合成酸碱双功能协同碳基纳米催化剂。以Henry和Knoevenagel碳碳键偶合为探针反应，研究限域孔道内不同酸碱活性位的分布、匹配、相对强度等因素对反应的影响以及协同催化机制，以期实现生物酶协同催化的高活性和高选择性。对介孔纳米碳球合成以及表面功能化系统深入的研究，不仅可以拓宽碳基纳米多孔材料的类型，也将为新型多功能仿生催化剂的设计合成提供充分的实验和理论依据。

介孔纳米球在纳米医药、光学器件、电池、纳米膜以及多相催化领域展现出了很好的应用前景, 尤其是易于扩散的具有树枝状孔道或者多级孔结构的介孔纳米球成为当前材料领域研究的热点。 但在介孔纳米碳球（颗粒尺寸<200 nm）的规模化制备（公斤级）、孔道结构调变（孔径>3.0 nm）、杂原子掺杂以及表面功能 化调控方面仍存在很多科学挑战。通关控制硅源和有机树脂前驱体水解和缩合反应速率的精准匹配， 利用硬-软-硬三相界面自纠缠（{O-, S+, I-} organic–surfactant–inorganic interface elf-entanglement）软模板合成策略一锅法率先实现了具有树枝状孔道结构和核-壳-冠结构的介孔纳米碳球的量化合成。经过碳化以及直接焙烧可以直接合成多种单相和多相碳/硅纳米球。 树枝状介孔纳米球由于纳米尺度的扩散路径和易于接触的活性中心，作为新颖的固体酸酸催化剂，在大分子参与的烷基化反应表现了最优的催化反应性能。本课题解决了软模板合成体系中如何精准控制具有不同水解和缩合反应化学的非兼容双相体系可控合成不同形貌和孔道结构的介孔纳米球的量化合成的关键科学问题。而且我们利用直接的实验和表征证据率先证明了树枝状孔道结构为连通的具有开放窗口的球形纳米笼的组装体， 可以成为新一代纳米反应器，相关的后续工作正在开展当中。