利用同步辐射X射线技术研究铜基原子簇催化剂在丙烯环氧化反应中的“构效关系”

丙烯环氧化反应是通过绿色化工生产环氧丙烷的关键环节，纳米铜对生成环氧丙烷有催化作用，但目前仍无法同时兼顾反应的活性与选择性。本项目将着重发展溶液相化学合成方法，以此获得形貌、尺寸均一的铜原子簇，通过催化性能测试，并结合原位结构表征方法，深入探索氧化物负载的铜催化剂在丙烯环氧化反应中的“构效关系”。具体研究中，本项目将以氧化硅、氧化铝为氧化物载体，利用基于沉积-沉淀法原理的水热制备方法，并通过引入表面活性剂改变载体表面的等电点，以此增强铜原子簇物种的稳定性。此外，本项目将通过催化性能测试得到与活性、选择性、稳定性相关的丙烯转化率、环氧丙烷产率、催化反应速率等实验数据，同时利用多通道原位X射线吸收精细结构谱学技术，可靠而高效的获取铜原子簇在丙烯环氧化反应中的结构变化过程，确定铜催化剂的活性中心。本项目最终期望能获得对于丙烯环氧化反应具有较好催化性能以及应用前景的新型铜原子簇催化材料。

Propene epoxidation reaction is the key step to produce propylene oxide via green chemical process. Nanosized copper can catalyze the formation of propylene oxide, but cannot achieve both activity and selectivity simultaneously. This proposal will focus on developing the solution-based chemical synthesis routes to obtain copper clusters with uniform size and shape. The catalytic performance of the copper catalysts will be tested for the propene epoxidation reaction. In-situ structural characterization means will be carried out to reveal the structure-activity relationship for oxide-supported copper cluster catalysts. Specifically, silica and alumina will be chosen as oxide supports for copper deposition. A hydrothermal approach on the basis of deposition-precipitation synthesis will be applied. Thermal stability of copper clusters will be improved by altering the isoelectric point of oxide surface of the used support with the addition of surfactant. The activity, selectivity and stability of copper catalysts will be reported according to the experimental data such as conversion of propylene, the yield of propylene oxide and the chemical reaction rate. Furthermore, in-situ X-ray absorption fine structure technique will be built and carried out to monitor the structural evolution on copper clusters reliably and efficiently, which can be used to identify the active sites of copper in catalytic reaction of propene epoxidation. The ultimate aim of this proposal is to develop new copper cluster catalysts with good catalytic performance and potential applications for the propene epoxidation reaction.