Freezing assisted fabrication of nano and micro hollow cubic metal oxides

摘要

Various embodiments provide materials and methods of forming hollow cubes. The hollow cubes can be formed to include a metal oxide shell layer encasing a cubic hollow space. In one embodiment, the hollow cubes can be formed from an emulsion having aqueous droplets with an interfacial layer encasing an aqueous core. By an exemplary freezing treatment, the aqueous droplets having a spherical shape can be transformed into ice components having a cubic shape. Metal oxide precursors can then be added to react with the encased cube-shaped ice core at the interface with the interfacial layer to form a sol-gel metal oxide shell layer. Hollow cubes can be formed by removing the cube-shaped ice core from the sol-gel metal oxide shell layer.