Au-Ag双金属团簇催化剂的设计合成及其催化甲基丙烯醛/甲醇氧化酯化反应性能研究

甲基丙烯醛/甲醇一步氧化酯化生成酯的反应在工业上具有重要应用。传统钯催化剂存在选择性差等问题。金催化剂在该反应中极具潜力，但金催化剂的低活性和低稳定性是限制其应用的瓶颈。本项目拟针对甲基丙烯醛/甲醇氧化酯化反应体系，（1）设计Ag原子掺杂的Au-Ag双金属纳米团簇，将其负载于MgO/MgAlOx等碱性材料上，研究其对氧化酯化催化性能的影响，通过调变配体基团种类，Au/Ag摩尔比，以及团簇的形貌、结构等，调控Au的微观结构和电子性质，以增强其对氧气分子的活化能力和在反应中的稳定性；（2）采用原位光谱表征和密度泛函理论计算方法，研究催化活性物种，解析中心原子配位环境，探究反应物分子及产物分子在催化剂上的吸附活化行为，从原子/分子水平揭示Ag原子掺杂对金催化剂结构和性质的调变以及对反应活性的影响，提出合理的反应模型，为设计高效、稳定的负载型双金属催化剂提供新思路，为深入理解催化反应机理提供指导。

Producing methyl methacrylate through one-step oxidation esterification from methyl acrolein and methanol has great important application in industry. While the traditional Pd-based catalyst suffers poor selectivity. Supported Gold catalysts have great potential in this reaction, but its low activity and bad stability are the main bottlenecks restricting their practical application. The project aims at oxidation esterification reaction system of methyl acrolein and methanol, to design of MgO/MgAlOx supported Au-Ag bimetallic alloy clusters, and apply them to the reaction. By adjusting the types of ligand groups, the mole ratio of Au/Ag, the morphology and structure of Au-Ag bimetallic clusters, the microstructure and electronic properties of Au are modulated. Thus, the capacity of the adsorption and activation of oxygen molecules and the stability of the catalyst could be enhanced. Further using in situ spectroscopic characterizations and density functional theory calculation methods, the active species of catalyst are investigated. The coordination environment of central atoms is analyzed. The adsorption and activation of reactant and product molecules on the catalysts are explored. Then, the effects of Ag atom doping on the structure and properties of the gold catalysts as well as the reactivity could be revealed from the atomic and molecular level. Thus, a reasonable reaction model could be proposed so as to provide new idea for the design of highly efficient and stable supported bimetallic catalysts, and supply guidance for the in-depth understanding of catalytic reaction mechanism.