金属纳米表面配位化学及其在炔基化合物选择性加氢催化中的应用

The surface and interfacial structures of supported metal nanocatalysts are important to their catalysis. However, due to the difficulties in fully characterizing their detailed structures, it remains great challenge to gain molecular insights into the structure-property correlation in supported metal nanocatalysts. With the aim to develop practical metal nanocatalysts for selective hydrogenation of alkynyl compounds, this proposed project will fabricate series of model metal nanocatalysts to simplify the structure characterizations of their surface and interface. These model nanocatalysts will be created from metal nanocrystals with well-defined surface and interface structures by modifying them with small inorganic or organic ligands. Various advanced techniques will be used to identify the detailed surface and interface structures of the fabricated model nanocatalysts, particularly their surface metal coordination structures. Together with spectroscopies, computational chemistry will be applied to understand the molecular mechanism on how the surface coordination influences the selective hydrogenation of alkynyl compounds. The ultimate goal of this project is to provide design principles for creating practical metal nanocatalysts for selective hydrogenation of alkynyl compounds. The project is composed of the following four parts: 1) the synthesis of mono- and bimetallic nanocrystals with three different surface structure features; 2) the surface modification of metal nanocrystals with small ligands and the characterization of their surface coordination structures; 3) understanding the molecular mechanisms on how the surface coordination structures determine the catalytic activity and selectivity in the hydrogenation of alkynyl compounds; 4) the application of the understanding over the structure-property correlation to create practical supported metal nanocatalysts.

针对实际负载型金属催化剂存在着其界面精细结构表征难、构-效关系本质难被揭示的特点，以炔基化合物选择性加氢为目标催化体系，本项目拟在制备具确定表面结构金属纳米晶体的基础上，构筑表界面结构相对明确的纳米模型催化材料，表征模型催化材料的表界面精细结构，特别是催化金属的表面配位结构，并结合先进谱学和理论计算在分子水平上认识相关材料的表面配位化学过程和炔基选择性加氢的催化机制，为实用高选择性炔基加氢催化剂的理性设计制备提供重要理论指导。项目研究主要包括如下四部分：1）制备具三种不同表面结构特征的单金属和双金属纳米晶体；2）金属纳米晶体的表面配位修饰与配位结构表征；3）纳米表面配位的催化效应及其活性和选择性的调控分子机理；4）将捕获的高活性、高选择性表面金属配位基元应用于实用负载型金属纳米催化剂的制备。项目有很好的研究基础，学科交叉性强，通过实施定能为高性能金属纳米催化剂的理性设计和合成提供重要指导。

针对真实催化剂表界面精细结构难被表征的特点，在构筑表界面结构相对明确的纳米模型催化材料体系的基础上，本项目在分子水平上解析了系列催化活性配位基元的结构，并深入理解活性基元参与的表界面催化化学过程，特别是对催化活性和选择性的调控分子机制。项目取得的成果主要体现在如下方面：（1）构筑配体保护的原子精确金属纳米簇和单原子分散催化这两类不同的金属纳米模型催化材料，揭示了表界面配位结构影响催化活性和选择性的分子机制；（2）系统发展了控制炔烃半氢化的两条不同热力学路径：I、通过位阻和电子效应，使烯烃中间体无法吸附于催化剂表面抑制第三个氢原子的插入；II、利用载体强碱性和H原子对的空间受挫抑制第四个H原子插入到活化后的C=C键；（3）发展了通过表面配位市校铜抗氧化防腐的全新方法和技术。执行期间，项目发表论文63篇，其中 Nature 1篇、 Nature Catal. 1篇、Nature Nanotechnol. 2篇、Chem. Rev. 1篇、Acc. Chem. Res. 1篇、J. Am. Chem. Soc. 8篇、Angew. Chem. Int. Ed. 9篇、CCS Chem. 2篇、Chem 3篇等；应邀为 Chem. Rev.、Acc. Chem. Res.、Nat. Nanotechnol.等撰写相关综述、展望文章；在 Natl. Rev. Sci.、 ChemNanoMat、 Sci. China Chem.上组织纳米催化相关专辑，形成了重要国际学术影响力；申请国家发明专利20件，其中授权专利12件。应邀在国际学术会议作大会报告1人次、主题/邀请报告8人次，在国内学术会议作主题/邀请报告 16 人次。