Hollow capsules of reduced graphene oxide nanosheets assembled on a sacrificial colloidal particle

We introduce a novel and versatile approach for preparing hollow multilayer capsules of graphene oxide nanosheets. Positively charged reduced graphene oxide (rGO-NH₃⁺) and negatively charged reduced graphene oxide (rGO-COO^-) were used as building blocks for the layer-by-layer assembly of graphene multilayer films onto polystyrene (PS) colloids. After removing the PS colloids with THF treatment, hollow graphene capsules with necessary physical and chemical stabilities were prepared successfully. Furthermore, we expand this approach in incorporating a new functionality such as gold nanoparticles into a hollow graphene capsule. SEM and TEM analyses suggest the successful preparation of multilayers of hollow graphene capsules and integration of gold nanoparticles into a hollow graphene capsule.