Generalized synthesis of yolk–shell metal oxide spheres

Varieties of yolk–shell metal oxide spheres, including SnO2, CeO2 and Tb4O7, with high yield have been successfully prepared via a general solvothermal method by using carbon spheres as sacrificial templates. The creation of yolk–shell structure is achieved after the removal of carbon templates by annealing. The results show that the typical products of yolk–shell SnO2 spheres exhibit excellent textural properties, which makes them good candidates for use in gas-sensing, energy storage, and so on. Many more metal oxides with such a unique yolk–shell structure can be easily prepared through the present approach, and they may show great application potentials.