Laboratory of Materials, Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, University of Carthage , Sidi Bou Said Road, B.P. 51, La Marsa 2070, Tunisia.
Faculté des Sciences de Tunis, Université de Tunis El Manar , Post Office Box 248, El Manar II, Tunis 2092, Tunisia.
Langmuir. 2017 Jul 18;33(28):7137-7146. doi: 10.1021/acs.langmuir.7b01247. Epub 2017 Jul 3.
Noble and precious metal catalysts are sought for their remarkable efficiency in catalyzing numerous reactions in heterogeneous phase. However, they are costly and require the development of high-surface-area supports that favor their strong immobilization, dispersion, and stability. Toward this end, mesoporous silica-based materials can be regarded as unique supports for nanometric-sized noble metal catalysts provided they are functionalized with appropriate ligands. In this work, mesoporous silica SBA-15 was prepared and modified with 3-azidopropyltriethoxysilane and then clicked with alkyne derivatives of 1,3,5-triazine complex ligand. The resulting hybrid material contains triazole and triazine moieties covalently bound to the mesoporous silica network. The triazole/triazine minidendron was immobilized through a 1,3-dipolar cycloaddition click reaction, which was monitored by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The heterocyclic ligand-functionalized SBA-15 material served as a hybrid reactive platform for in situ deposition of palladium nanoparticles whose size is 3.154 ± 0.49 nm as assessed by X-ray diffraction and confirmed by transmission electron microscopy. The catalytic performance of the final palladium-decorated hybrid triazole/triazine-functionalized SBA-15 support was evaluated in the model reduction of 4-nitrophenol to 4-aminophenol by catalytic hydrogenation and stoichiometric reduction. Excellent catalytic performances were achieved, with reduction rate constant (K) of 16.8 × 10 s for this model reaction. Moreover, the hybrid catalyst can be produced in high yield and recycled.
贵金属催化剂因其在多相催化中对许多反应的高效性而备受关注。然而，它们成本高昂，需要开发高表面积的载体来促进其强固定、分散和稳定性。为此，介孔硅基材料可被视为纳米级贵金属催化剂的独特载体，只要它们用适当的配体官能化。在这项工作中，制备了介孔硅 SBA-15，并对其进行了 3-叠氮丙基三乙氧基硅烷的修饰，然后与 1,3,5-三嗪配体的炔衍生物进行点击反应。所得的杂化材料含有共价键合到介孔硅网络上的三唑和三嗪部分。三唑/三嗪树枝状低聚物通过 1,3-偶极环加成点击反应固定在介孔硅上，该反应通过傅里叶变换红外光谱和 X 射线光电子能谱进行监测。杂环配体功能化的 SBA-15 材料作为原位沉积钯纳米粒子的混合反应平台，钯纳米粒子的尺寸通过 X 射线衍射评估为 3.154±0.49nm，并通过透射电子显微镜确认。最后，钯修饰的杂化三唑/三嗪功能化 SBA-15 载体的催化性能在 4-硝基苯酚模型还原为 4-氨基酚的催化氢化和化学计量还原中进行了评估。该模型反应的还原速率常数（K）达到了 16.8×10 s，实现了优异的催化性能。此外，该杂化催化剂可以高产率制备并回收利用。
