Covalent organic frameworks (COFs) with well-defined and customizable pore structures are promising templates for the synthesis of nanomaterials with controllable sizes and dispersity. Herein, a thioether-containing COF has been rationally designed and used for the confined growth of ultrafine metal nanoparticles (NPs). Pt or Pd nanoparticles (Pt NPs and Pd NPs) immobilized inside the cavity of the COF material have been successfully prepared at a high loading with a narrow size distribution (1.7 ± 0.2 nm). We found the crystallinity of the COF support and the presence of thioether groups inside the cavities are critical for the size-controlled synthesis of ultrafine NPs. The as-prepared COF-supported ultrafine Pt NPs and Pd NPs show excellent catalytic activity respectively in nitrophenol reduction and Suzuki–Miyaura coupling reaction under mild conditions and low catalyst loading. More importantly, they are highly stable and easily recycled and reused without loss of their catalytic activities. Such COF-supported size-controlled synthesis of nanoparticles will open a new frontier on design and preparation of metal NP@COF composite materials for various potential applications, such as catalysis and development of optical and electronic materials.

中文翻译：

---

含硫醚共价有机骨架的超细高分散金属纳米粒子的合成及其催化应用

具有良好定义和可定制孔结构的共价有机骨架（COF）是合成具有可控制的尺寸和分散度的纳米材料的有希望的模板。在此，已经合理地设计了含硫醚的COF，并将其用于超细金属纳米颗粒（NP）的有限生长。固定在COF材料腔内的Pt或Pd纳米颗粒（Pt NP和Pd NPs）已经成功地以高负载，窄尺寸分布（1.7±0.2 nm）制备了。我们发现，COF载体的结晶度和腔体内硫醚基团的存在对于超细NP的尺寸控制合成至关重要。制备的COF负载的超细Pt NPs和Pd NPs在温和的条件下和低催化剂负载量下，在硝基苯酚还原反应和Suzuki-Miyaura偶联反应中分别显示出优异的催化活性。更重要的是，它们是高度稳定的，易于回收和再利用，而不会损失其催化活性。这种由COF支持的尺寸控制的纳米颗粒合成方法将为金属NP @ COF复合材料的设计和制备打开新的领域，以用于各种潜在应用，例如光学和电子材料的催化和开发。