基于表界面结构调控的夹层铈基纸型催化剂构筑及其协同催化机制研究

Nowadays, the paper catalyst is one of the research hotspot in the fields of materials and catalysis, favored by its low specific gravity, high porosity and excellent gas-diffusion properties. In order to design novel paper catalysts with high catalytic properties, the synergetic reaction mechanism is the key scientific problem to be solved urgently. In this proposal, the ceria-based oxide fibers and ceria-based oxide coating carbon fibers are chosen as matrix fibers of "core" layer and "cladding" layer towards the ceria-based sandwich paper catalyst, respectively. The formation mechanisms of the matrix fibers will be studied thoroughly to develop a new way for the optimization of surface&interface structure. Then, the influence factors for the CO catalytic efficency including the intrinsic structural regulation of the matrix fibers, the junction effects of inorganic binders, and optimization of the "core-cladding" interface structure, will be researched systemically to have a clear relationship between the catalyst structure and reaction performance. Finally, the synergetic mechanisms for the CO catalytic oxidation will be disclosed by analyzing the complicated "interface effects" of the ceria-based sandwich paper catalyst via the XPS, In-situ IR spectra techniques, which can guide the functional design of paper catalyst.

纸型催化剂具有比重小、孔隙率高和气体扩散性能好的优点，成为当前材料与催化领域的研究热点之一。但是，纸型催化剂的协同催化机制尚不清楚，成为构筑新型高效纸型催化剂的瓶颈，也是亟待解决的关键科学问题。本项目针对纸型催化剂提出“夹层结构”的设计新思路，其中“芯”层为大比表面积和长径比铈基氧化物纤维构成的功能层，“覆”层为不同形貌结构铈基氧化物涂层碳纤维构成的结构层。通过研究“芯”层纤维的形成机制和“覆”层纤维的原位生长机制，探索夹层铈基纸型催化剂的表界面结构调控新途径。同时，选择CO催化氧化反应为模型反应，利用X射线光电子能谱、拉曼光谱、原位红外光谱等手段，分析基体纤维本征结构调控、无机粘结剂的串联效应和“芯-覆”层界面结构优化对载体表面活性氧环境和催化反应动力学过程的影响，深入剖析铈基纸型催化剂多层次体系的“表界面效应”，建立反应构效关系并揭示协同催化机制，从而为纸型催化剂的功能性设计提供指导。

纸型催化剂具有比重小、气体和热量的传输效率高的独特优点，是当前环境与能源催化领域的研究热点之一。围绕纸型催化剂反应构效关系及其协同催化机制这一关键科学问题，该项目首次从基体纤维功能性设计角度出发，利用干法纺丝工艺研制了均一性良好的铈基氧化物（CeO2-ZrO2，CeO2-TiO2等）纤维，并以其为主要基体制备了具有优异力学性能和催化活性的铈基纸型催化剂。同时，以活性氧的产生与转移为切入点，研究了不同基体纤维与活性组分之间的协同催化效应。此外，项目提出了夹层设计思路，将铈基氧化物纤维作为芯层，力学性能优异的莫来石纤维作为覆层，分别采用物理压榨和湿法成型技术制备具有夹层结构的铈基纸型催化剂。为了强化“芯-覆”层的关联效应，利用水蒸汽处理手段在活性炭纤维表面制备了具有良好均一性和结合力的CeO2-ZrO2涂层，使之作为“覆层”纤维。项目开拓了纸型催化剂功能性设计的新路径，完善了相关技术和理论体系，为促进其实际应用提供了良好的基础。