多相催化中的电子助催剂作用机制研究

助催剂包括结构和电子两大类，在多相催化中常用来稳定催化剂结构和提高催化性能。原子层次上电子助催剂的微观作用机制研究至今甚少。本项目利用超高空间分辨的扫描探针显微镜、表面科学技术、催化表征方法和理论模拟与计算研究金属和负载型金属模型催化剂表面上电子性助催剂对催化剂金属表面的结构、电子性质以及探针分子的活化与反应性质的微观作用机制。这涉及不同助催剂对导电性的金属模型催化剂以及弱导电性乃至绝缘的负载型金属模型催化剂表面的助催作用。项目选用CO加氢或氧化，CO2解离或加氢、N2解离和乙烯环氧化反应作为催化探针反应，碱金属Na、K和Cs及其氧化物以及卤素元素Cl和Br及其化合物为助催剂。

Promoters can be categorized into structural and electronic ones which are frequently employed to stabilize structures and augment catalytic performances of heterogenous catalysts, respectively. The working mechanisms of electronic promoters at the atomic level are, however, rarely explored before. In the project, ultra-high spatial resolution scanning probe microscopy, surface science techniques, catalysis characterization methodologies as well as theoretical simulations and calculations will be utilized to study the effects of electronic promoters on surface structures, electronic properties, molecular activations and catalytic reactions of metal and supported metal catalysts. It involves two types of electronic promoters, namely, alkali elements and their oxides as well as halogen elements and their compounds, on conducting metal catalysts and weakly conducting or insulating supported metal catalysts. Selected probe reactions include CO hydrogenation or oxidation, CO2 decomposition or hydrogenation, N2 dissociation and ethylene epoxidation. Targeted electronic promoters consist of alkali Na, K, Cs and their oxides as well as halogen elements Cl, Br and their compounds.