Cluster–Cluster Co‐Nucleation Induced Defective Polyoxometalate‐Based Metal–Organic Frameworks for Efficient Tandem Catalysis
Songzhu Xing, Xujiao Ma, Qingqing Gu, Nana Ma, Zhong Zhang, Guoying Han, Rui Huang, Xiao Feng, Bing Yang, Chunying Duan, Yiwei Liu
Abstract
Abstract The construction of defective sites is one of the effective strategies to create high‐activity Metal–Organic frameworks (MOFs) catalysts. However, traditional synthesis methods usually suffer from cumbersome synthesis steps and disordered defect structures. Herein, a cluster–cluster co‐nucleation (CCCN) strategy is presented that involves the in situ introduction of size‐matched functional polyoxometalates (H 6 P 2 W 18 O 62 , {P 2 W 18 }) to intervene the nucleation process of cluster‐based MOFs (UiO‐66), achieving one‐step inducement of exposed defective sites without redundant post‐processing. POM‐induced UiO‐66 ({P 2 W 18 }‐0.1@UiO‐66) exhibits a classical reo topology for well‐defined cluster defects. Moreover, the defective sites and the interaction between POM and skeletal cluster nodes are directly observed by Integrated Differential Phase Contrast in Scanning Transmission Electron Microscopy (iDPC‐STEM). Owing to the molecular‐level proximity between defective sites and POM in the same nano‐reaction space, {P 2 W 18 }‐0.1@UiO‐66 exhibits efficient tandem catalysis in the preparation of γ‐valerolactone (γ‐GVL) from laevulinic acid (LA) by the combination of Lewis and Brønsted acids with 11 times higher performance than defective UiO‐66 formed by conventional coordination modulation strategy. The CCCN strategy is applicable to different POM and has the potential to be extended to other cluster‐based MOFs, which will pave a new way for the construction of functional MOFs with multi‐centered synergistic catalysis.