Self-templated route to synthesis bowl-like and deflated balloon-like hollow silica spheres

Hollow silica spheres (HSS) have attracted considerable attention in recent years because of their unique physical and chemical properties, as well as can be used for wide range potential applications. In this study, a novel HSS was successfully synthesized via silica sol self-templated route and vacuum freeze-drying assistant method. The experimental results revealed that the HSS exhibited bowl-like and deflated balloon-like morphology structure and thin sphere shell was approximately 30 nm. The particle size of the HSS was almost between 0.20 and 2.50 µm. The possible mechanism for the formation of the HHS was discussed and proposed.