One-pot synthesis of thermally stable gold@mesoporous silica core-shell nanospheres with catalytic activity

A facile one-pot method has been developed to synthesize uniform gold@mesoporous silica nanospheres (Au@MSNs), which have a well-defined core-shell structure with ordered mesoporous silica as a shell. The resulting Au@MSNs have a high surface area (∼521 m2/g) and uniform pore size (∼2.5 nm) for the mesoporous silica shell. The diameter of the gold core can be regulated by adjusting the amount of HAuCl4. The catalytic performance of the Au@MSNs was investigated using the reduction of 4-nitrophenol as a model reaction. The mesopores of the silica shells provide direct access for the reactant molecules to diffuse and subsequently interact with the gold cores. In addition, the Au@MSNs display the great advantage of sintering-resistance to 950 °C because the mesoporous silica shells inhibit aggregation or deformation of the gold cores. The high thermal stability enables the Au@MSNs to be employed in high-temperature catalytic reactions.