Topological transformation of thioether-bridged organosilicas into nanostructured functional materials

The strong interest in nanostructured functional materials has motivated the scalable production of high quality mesoporous silicas and carbonaceous materials. Although many approaches have been explored for this goal, it is highly desired and still remains a challenge to develop a straightforward strategy for simple and cost-effective fabrication of nanostructured functional materials. Here we demonstrate a simple sol-gel preparation of bis[3-(triethoxysilyl)propyl]tetrasulfide-based organosilica nanostructured materials and their topological transformations, through which porous spherical silica or carbon and hollow silica or carbon capsule are synthesized. As a representative application, the hollow carbon capsule is employed as a catalyst support for dispersion of high loading of Pt, which exhibits much higher catalytic activity toward oxygen reduction reaction than other porous carbon materials prepared in this work due to its larger surface area and mesoporous volume, particularly the unique architecture composed of a hollow macroporous core and a mesoporous shell, facilitating not only small size and good dispersion of Pt nanoparticles but also fast mass transport.