Anisotropic porous Co3O4 nanocapsules and their evolution process. (a) Schematic presentation of the evolution process of anisotropic Co3O4 porous nanocapsules. (b) Low-magnification SEM image showing that these nanocapsules are nearly monodisperse. (c) Low-magnification TEM image showing the porous shell of anisotropic Co3O4 nanocapsules. (d) High-magnification TEM image exhibiting a single, porous Co3O4 nanocapsule. (e) HRTEM image of individual nanocrystals revealing the (111) lattice plane. Adapted from  and reproduced with the permission of the Royal Society of Chemistry.
Liu et al. Nanoscale Research Letters 2012 7:149 doi:10.1186/1556-276X-7-149