多孔棒状铈基氧化物负载金催化剂结构调控及催化醛氧化酯化反应性能研究

At present, the Au catalysts applied for oxidative esterification of aldehyde to ester are easy to aggregate leading to the decrease of activity and additional base is needed. This project is focused on the preparation and controllable mechanism of a novel porous Ce-based nanorod supported Au catalysts. First, the porous Ce-based nanorods were prepared by hydrothermal using ionic liquids as solvent and template. The porous structure, alkalinity, reducibility and morphology of support will be tuned by changing chain length, doped element and varying hydrothermal condition. Following this, the highly dispersed and stable Au catalysts were prepared by deposition-precipitation and colloid deposition. Further, the correlation between the alkalinity, reducibility of support and catalytic performance, the regularity of improving the dispersity and stability of Au particles, in-situ detection of intermediates, DFT calculation, the mechanism and the kinetic model of the direct oxidative esterification reaction will be investigated in this project. The above-mentioned investigations contribute to the development of efficient and stable Au catalysts, and the theory and methodology drawn from this project will be referenced widely in the development of other noble metal-based catalysts.

现有负载金催化剂用于醛氧化酯化反应易积聚、稳定性差、需加固体碱，难以实际应用。本项目拟采用离子液体辅助水热合成多孔棒状铈基材料，进一步制备其高分散高稳定金催化剂。首先，以咪唑类离子液体为溶剂和模板剂水热制备多孔棒状铈基材料，通过掺杂不同元素、改变支链长度和水热条件，实现对载体孔结构、碱性、还原性和形貌的控制，然后，以沉积沉淀法和溶胶沉积法制备高分散高稳定负载的纳米金催化剂。通过研究催化剂的性能与载体物化性质的关系，揭示载体碱性和还原性增强催化活性的机制，掌握多孔结构提高金粒子的分散度和稳定性规律。运用原位光谱检测中间体、计算模拟过渡态等方法，阐明醛氧化酯化反应机理，构建反应过程动力学模型。本项目的研究将为高效稳定金催化剂的设计、开发以及工业化推广提供重要的理论基础和实践指导。

醛氧化酯化制备酯比传统两步法工艺简化过程绿色。现有金催化剂比传统钯基催化剂成本低、活性高，但金催化剂存在易积聚稳定性差和分离成本高等问题，发展高效稳定易分离金催化剂是提高此清洁工艺竞争优势的迫切需求。本项目采用离子液体辅助水热法开发了不同磁性元素掺杂的多孔铈基材料作为载体，进一步采用均匀沉淀法制备了高分散纳米金催化剂。针对提高金催化剂性能、稳定性、分离难的关键科学问题，重点研究多孔磁性铈基材料和金粒子协同催化醛氧化酯化的构效关系，研究离子液体辅助水热调控铈基材料孔结构、碱性、氧化还原性和磁性的机制，通过不同时间产物和反应物随时间变化，获得反应过程的动力学模型；研究不同元素掺杂，对于载体磁性的影响， 揭示金和载体强相互作用机理及金纳米颗粒稳定机理和催化醛氧化酯化机理，为高效稳定金催化剂的设计提供科学依据。本项目的成功实施将为高性能、高稳定、易分离催化剂的设计、开发以及工业化推广提供重要的理论基础和实践指导。