Fabrication of Ellipsoidal Silica Yolk-Shell Magnetic Structures with Extremely Stable Au Nanoparticles as Highly Reactive and Recoverable Catalysts

作者：Fang, Jiasheng; Zhang, Yiwei^*; Zhou, Yuming^*; Zhao, Shuo; Zhang, Chao; Zhang, Hongxing; Sheng, Xiaoli; Wang, Kunpeng

来源：Langmuir, 2017, 33(11): 2698-2708.

DOI：10.1021/acs.langmuir.6b03873

• CORE-SHELL
• GOLD NANOPARTICLES
• POROUS SHELL
• HOLLOW
• NANOCATALYSTS
• OXIDATION
• REDUCTION
• CARBON
• MICROSPHERES
• NANOSPHERES

A novel strategy was reported for the fabrication of yolk shell magnetic MFSVmS-Au nanocomposites (NCs) consisting of double-layered ellipsoidal mesoporous silica shells, numerous sub-4 nm Au nanoparticles (NPs), and magnetic Fe central cores. The hierarchical FSVmS NCs with ellipsoidal alpha-Fe2O3@mSiO(2)/mSiO(2) as yolks/shells were first prepared through the facile sol gel template-assisted method, and plenty of extremely stable ultrafine Au NPs were postencapsulated within interlayer cavities through the unique deposition precipitation method mediated with Au(en)(2)Cl-3 compounds. Notably, ethylenediamine ligands were used to synthesize the stable cationic complexes, [Au(en)(2)](3+), that readily underwent the deprotonation reaction to chemically modify negatively charged mesoporous silica under alkaline conditions. The subsequent two-stage programmed hydrogen annealing initiated the in situ formation of Au NPs and the reduction of alpha-Fe2O3 to magnetic Fe, where the synthesized Au NPs were highly resistant to harsh thermal sintering even at 700 degrees C. Given its structural superiority and magnetic nature, the MFSVmS-Au was demonstrated to be a highly efficient and recoverable nanocatalyst with superior activity and reusability toward the reduction of 4-nitrophenol to 4-aminophenol, and the pristine morphology was retained after six recycling tests.

• 出版日期2017-3-21
• 单位东南大学