Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, P.R. China.
University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
Nano Lett. 2022 Jan 26;22(2):838-845. doi: 10.1021/acs.nanolett.1c04574. Epub 2022 Jan 10.
Defects in solid materials vitally determine their physicochemical properties; however, facile regulation of the defect density is still a challenge. Herein, we demonstrate that the ligand defect density of metal-organic frameworks (MOFs) with a UiO-66 structural prototype is precisely regulated by tuning the linker groups (X = OMe, Me, H, F). Detailed analyses reveal that the ligand defect concentration is positively correlated with the electronegativity of linker groups, and Ce-UiO-66-F, constructed by F-containing ligands and Ce-oxo nodes, possesses the superior ligand defect density (>25%) and identifiable irregular periodicity. The increase in ligand defect density results in the reduction of the valence state and the coordination number of Ce sites in Ce-UiO-66-X, and this merit further validates the relationship between the defective structure and catalytic performance of CO cycloaddition reaction. This facile, efficient, and reliable strategy may also be applicable to precisely constructing the defect density of porous materials in the future.
固体材料的缺陷对其物理化学性质至关重要；然而，方便地调节缺陷密度仍然是一个挑战。在此，我们证明了具有 UiO-66 结构原型的金属有机骨架（MOFs）的配体缺陷密度可以通过调节连接基团（X = OMe、Me、H、F）来精确调控。详细分析表明，配体缺陷浓度与连接基团的电负性呈正相关，并且由含氟配体和 Ce-氧节点构建的 Ce-UiO-66-F 具有较高的配体缺陷密度（>25%）和可识别的不规则周期性。配体缺陷密度的增加导致 Ce-UiO-66-X 中 Ce 位点的价态和配位数降低，这进一步验证了缺陷结构与 CO 环加成反应催化性能之间的关系。这种简便、高效、可靠的策略在未来也可能适用于精确构建多孔材料的缺陷密度。
