Jiang Yilin, Yu Yuan, Zhang Xu, Weinert Micha, Song Xueling, Ai Jing, Han Lu, Fei Honghan
Shanghai Key Laboratory of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, 1239 Siping Rd., Shanghai, 200092, China.
Angew Chem Int Ed Engl. 2021 Aug 2;60(32):17388-17393. doi: 10.1002/anie.202105420. Epub 2021 Jun 30.
Ultrafine gold nanoclusters (Au-NCs) are susceptible to migrate and aggregate, even in the porosity of many crystalline solids. N-heterocyclic carbenes (NHCs) are a class of structurally diverse ligands for the stabilization of Au-NCs in homogeneous chemistry, showing catalytic reactivity in CO activation. Herein, for the first time, we demonstrate a heterogeneous nucleation approach to stabilize ultrasmall and highly dispersed gold nanoclusters in an NHC-functionalized porous matrix. The sizes of gold nanoclusters are tunable from 1.3 nm to 1.8 nm based on the interpenetration of the metal-organic framework (MOF) topology. Control experiments using amine or imidazolium-functionalized MOFs afforded the aggregation of Au species. The resultant Au-NC@MOF composite exhibits a steady and excellent activity in photocatalytic CO reduction, superior to control mixtures without NHC-ligand stabilization. Mechanistic studies reveal the synergistic catalytic effect of MOFs and Au-NCs through the MOF-NHC-Au covalent-bonding bridges.
即使在许多晶体固体的孔隙中，超小金纳米团簇（Au-NCs）也容易迁移和聚集。N-杂环卡宾（NHCs）是一类结构多样的配体，用于在均相化学中稳定Au-NCs，在CO活化中表现出催化活性。在此，我们首次展示了一种非均相成核方法，用于在NHC功能化的多孔基质中稳定超小且高度分散的金纳米团簇。基于金属有机框架（MOF）拓扑结构的相互贯穿，金纳米团簇的尺寸可在1.3 nm至1.8 nm之间调节。使用胺或咪唑鎓功能化的MOF进行的对照实验导致Au物种聚集。所得的Au-NC@MOF复合材料在光催化CO还原中表现出稳定且优异的活性，优于没有NHC配体稳定化的对照混合物。机理研究揭示了MOF和Au-NCs通过MOF-NHC-Au共价键桥的协同催化作用。
