介孔分子筛孔内近邻耦合双金属物质的精准构筑及催化性能研究

The near-neighboring and coupling interaction of multi-component metals in heterogeneous catalytic reactions facilely trigger synergistic catalytic effect, but, the strategic design and precise construction of this type of active species on the support remain challenged. This project is guided with the design and synthesis of functional mesoporous silica, in which a multi-components-bearing mesoporous molecular sieve catalyst with dense near-neighboring and coupling catalytic active sites is synthesized through the combined techniques of in-situ embedding of active metal, progressively-oriented re-adsorption of active center and the controlled surface oxidation remodeling procedure inducing the integrated decoration of bimetallic compositions on the porous surface of mesoporous silica. Based on the matching of transition metals (Cu, Fe, Co, Ni) and the change of their introduction order, together with the surface oxidation control program, the state of the bimetallic active components was finely regulated and optimized, and then multifarious characterization and testing techniques are utilized to explore the position relationship and coupling effect between the metal components to identify the key factors of the preparation of supported synergistic catalysts. In this case, their improving catalytic mechanism derived from near-neighboring and coupling effect and reasonable reaction model are further studied based on the catalytic property assessment in the oxidative amidation of the aromatic alcohols, an important chemical reactions in the synthesis of biomedical chemicals. The implementation of this project will be beneficial to innovate the design of highly-efficient catalyst, providing more technical support for collaborative catalysis study.

多相催化反应中多组分金属间的近邻与耦合作用易获得协同的催化效应，但载体上此类活性物质的策略设计与精准构筑仍然极具挑战。本项目以功能型介孔分子筛的设计合成为导向，拟采用金属原位嵌入、渐进式活性中心定向再吸附及表面氧化重构的组合技术对介孔氧化硅的孔道进行双金属的集成修饰，合成含高密度近邻耦合作用活性位的多组分介孔分子筛催化剂。以过渡金属（Cu、Fe、Co、Ni）间的搭配及其引入次序变换，结合表面氧化控制程序对双金属活性物质状态进行精细调控与优化，并结合多种表征测试技术探究金属组分间存在的位置关系与作用耦合效应，考察负载型协同催化剂制备的关键因素。在此基础上，以生命医药化学品合成中的重要化学反应-芳醇氧化酰胺化为探针，评价所得催化剂的催化性能，研究双金属组分间产生的近邻与耦合作用对其催化性能的提高机制及反应机理。本项目的实施有助于创新高效催化剂设计，为协同催化研究提供更多的技术支持。

金属间的协同作用在催化反应中常伴随着催化性能的提升与促进，因此构建金属的协同效应在多相催化反应中具有显著的意义。本项目从分子筛的设计出发，结合胶束配位金属诱导介孔分子筛中孔道的原位修饰及二次金属的邻近与改性。结合金属在介孔分子筛表面的分布和相互作用形式，研究了金属状态与催化剂反应性能间的关系。尤其通过建立的金属间相互作用探讨了反应分子在催化位点的吸附与相互作用及化学键的活化过程。此外，通过电纺技术，本项目拓展了特殊结构催化剂的合成制备技术，合成了双金属构建的钴锰尖晶石纤维纳米催化剂。通过热处理的过程控制，实现了纤维催化剂的界面工程效应，使催化剂在反应过程中拥有更多的反应活性区域，同时双金属在热驱动的过程中使尖晶石表明的氧空位状态得到调控，因此在PMS活化中具有显著的反应活性，研究内容讨论了氧空位在PMS活化过程中的关键作用，揭示了其活性提升机制。