Silica nanorattle with a mesoporous shell and tunable gold core was successfully fabricated by the Laboratory of Controllable Preparation and Application of Nanomaterials, led by Prof. Fangqiong Tang from Technical Institute of Physics and Chemistry at Chinese Academy of Sciences. The relevant results have been published in a recent online issue of Advanced Materials titled by 'A Silica Nanorattle with a Mesoporous Shell: An Ideal Nanoreactor for the Preparation of Tunable Gold Cores' (Adv. Mater., DOI:10.1002/adma.201002277).

Recently, much attention has been paid to noble metals nanoparticles due to their unique catalytic properties that are not revealed in their bulk forms. The goal of keeping noble metals nanoparticles with both high activity and stability have been pursued by materials scientists for many years. The encapsulation of metal core into hollow nanosphere with mesoporous shell provides an effective strategy to resolve this problem.

This research group has fabricated a unique nanostructure with independent intellectual property, silica nanorattle, which has a hollow cavity and a mesoporous shell. The sphere sizes, the middle cavities’ volume, the thickness of mesoporous shell can be controlled precisely. Moreover, the mesoporous shell allows the diffusion of small active molecules in and out of the nanosphere. Meanwhile, the inside of the silica nanorattle has plenty of reactive groups, which can be used as in situ reducing agent and stabilizer for the growth of noble metal core. Taking advantage of these reactive groups and the hollow cavity, the researchers fabricated size-tunable gold core in the hollow cavity by using the silica nanorattle as ideal nanoreactor.

This kind of gold core silica nanorattle was successfully applied in the catalytic reduction of 2-nitroaniline as a model reaction, showing great activity after catalytic reaction for 5 cycles. In addition, the synthesis method is quite simply and easy to scale up, and the strategy can be extended to fabricated hollow silica nanoparticles with other noble metal cores and noble metal nanoparticles on other silica nanostructures.

The relevant work has been applied for a Chinese patent.