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 ℃ 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.