中空导电聚合物负载纳米金催化剂的稳定机制及催化机理研究

The life of the supported Au catalysts, i.e. long-term catalytic stability, is one of the key points in their large-scale application. In this work, we will prepare hollow Au/copolymerized conductive polymers (CCPs) catalysts via the stabilization of conjugated heteroatom of conducting polymers to Au nanoparticles. Through the optimization of constitution and polymerization conditions of CCPs monomer, the influence of the kind, proportion and doping state of heteroatoms in CCPs in the stability of Au nanoparticles and catalytic properties will be studied together with the interaction between heteroatoms and Au nanoparticles, and further clarifying the catalytic stabilization mechanism of CCPs-supported Au catalysts. Highly stable Au/CCPs catalysts with good catalytic performances will be subsequently achieved. By virtue of the interaction between heteroatoms and Au nanoparticles, the controllable electron transfer between CCPs and Au can be realized by means of controlling the direction and intensity of electron gain or loss of CCPs and thus a series of hollow Au/CCPs catalysts with specially appointed chemical state are obtained. The CO oxidation and the hydrogenation of 4-nitrophenol are tested as the probe reactions to study the catalytic activities and recycling stability of the catalysts with an attempt to reveal the catalytic mechanism of Au with different chemical states. This project will provide theory instruction and experimental basis for the application of conducting polymers-supported nanogold catalysts.

负载型金催化剂的使用寿命即长期催化稳定性是决定其大规模应用的关键所在。本项目拟采用导电聚合物共轭杂原子稳定纳米金粒子的策略制备中空Au/共聚导电聚合物(CCPs)催化剂。通过对CCPs共聚单体组成及其聚合条件的优化，探究CCPs壳层共轭杂原子的种类、配比及其掺杂状态对金催化剂催化活性及稳定性的影响，研究共轭杂原子与金的相互作用，给出CCPs负载纳米金催化剂的稳定机制，获得高活性高稳定的Au/CCPs催化剂。在此基础上，借助共轭杂原子与金之间的相互作用，通过控制CCPs层电子迁移的方向和强度，实现CCPs与金之间电子的可控转移，获得一系列具有特定金化学状态组成的Au/CCPs催化剂。以CO氧化反应和对硝基酚还原反应为探针，考察该系列催化剂的催化活性和循环使用稳定性，揭示不同化学状态组成下的金催化反应机理，为导电聚合物负载纳米金催化剂的应用开发奠定理论和实验基础。

本项目围绕导电聚合物负载纳米金催化剂的制备及其稳定性方面开展研究，以期解决纳米金催化剂的使用寿命问题。采用导电聚合物稳定纳米金的策略制备高稳定长寿命的纳米金催化剂。通过对载体导电聚合物的形貌调控（核壳、中空微米管或梭形）、金负载方式的优化（金胶吸附法、聚合物原位还原法）、Au载量的选择等，最终获得高活性高稳定的纳米金催化剂。研究发现导电聚合物共轭杂原子与纳米金之间存在着电子的强相互作用，这种相互作用是获得高稳定纳米金催化剂的关键。且可以通过对催化剂制备方式的调变获得不同Au化学状态的催化剂。在前期研究的基础上，为解决催化剂的循环使用问题制备了磁性核壳导电聚合物负载的纳米金催化剂，在对硝基酚加氢反应中经15次循环，该催化剂的活性没有明显降低，表现出优异的稳定性。此外，本项目设计了CeO2改性Al2O3负载纳米金催化剂、Au-Mn改性ZSM-5催化剂、锆基及镨基氧化物负载纳米金等多款纳米金催化剂，并研究了其在乙炔加氢、轻柴油催化裂化增产丙烯、丙烯环氧化、水煤气变换、富CO2气氛下CO氧化等反应的应用。探讨催化剂的构效关系与反应机理，从金纳米粒子尺寸、金负载量、金化学状态等方面考察催化剂的催化活性和稳定性，获得了一些有益的结论，为解决催化剂的稳定性方面提供了一些实验基础与理论借鉴，同时也为金催化剂的工业应用提供科学指导。