Aminosilane decorated carbon template-induced in situ encapsulation of multiple-Ag-cores inside mesoporous hollow silica

A dispersed and stable catalytic active phase and a protective reaction environment are acknowledged as ideal metal catalyst characteristics. In this paper, a cores@shell structure of microreactor with a well-dispersed active phase of multiple free-Ag-cores, hollow cavity and protective mesoporous shell was prepared by a simple and novel construction approach. The organic ligand of aminosilane (APTES) was directly incorporated on carbon nanospheres to anchor Ag ions as a metallotemplate, which avoids the tedious steps of conventional methods, and then the sacrificed metallotemplate was employed for directly fabricating the special hollow mesoporous silica microreactors. As a result, multiple free active Ag-cores were in situ produced and encapsulated in the cavity of hollow mesoporous silica during the thermal process. The important evidence of the configuration including a big hollow cavity containing active multiple-Ag nanoparticles and a mesoporous SiO₂-shell can be demonstrated with efficient techniques including XRD, FT-IR, XPS, BET, SEM and TEM. Just as expected, the catalyst as a functional microreactor exhibited a high catalytic activity for the liquid-reduction of 4-nitrophenol, and the increasing dosage of used catalyst contributes to the enhancing of catalytic activity. The methodology demonstrated here provides a new insight for the fabrication of versatile functional nanomaterials with noble or transition metals inside a hollow shell.