title: One-pot synthesis of M (M = Ag, Au)@SiO2 yolk-shell structures via an organosilane-assisted method: preparation, formation mechanism and application in heterogeneous catalysis.
abstract: We demonstrate the fabrication of yolk-shell catalysts consisting of a single M (M = Ag, Au) nanoparticle encapsulated within a hollow mesoporous organosilica shell via an organosilane-assisted strategy. The advantages of our method lie in its good controllability of the void space as well as the thickness of the mesoporous shell. The M@CTAB/SiO2 synthesized through a modified Stöber method can transform to yolk-shell structures after adding (3-aminopropyl)trimethoxysilane (APTMS)/TEOS or (3-aminopropyl)triethoxysilane (APTES)/TEOS into the synthetic medium. We give unambiguous evidence that the middle CTAB/SiO2 layer transforms into a less dense APTMS-rich organic-inorganic layer which was selectively removed in alkaline aqueous solution, while the amino-functionalized hybrid shells remain intact. Moreover, we discuss the role of alkylamino groups in the shell in the transformation from Ag@SiO2 nanorattles to hollow structures when impregnating the as-synthesized Ag@SiO2 nanorattles in HAuCl4 aqueous solution. The nanorattles also exhibit high catalytic activity for the catalytic reduction of p-nitrophenol.
authors: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China. wangqh@licp.cas.cn.
authors: Yu
authors: Y
authors: Chen
authors: Qihua
authors: Q
authors: Wang
authors: Tingmei
authors: T
authors: Wang
mesh_terms: D000627:Aminophenols / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry; D009596:Nitrophenols / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D016062:Porosity; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000627:Aminophenols; D009596:Nitrophenols; D012821:Silanes; D012834:Silver; D006046:Gold; D012822:Silicon Dioxide; C026729:4-aminophenol; C024836:4-nitrophenol