Fe3O4 nanoparticles, α-Fe2O3 hollow spheres, and the two-step electrode design. (a, b) TEM images of Fe3O4 nanoparticles encapsulated within carbon shells anchoring on RGO sheets. Adapted from  and reproduced with the permission of the Royal Society of Chemistry. (c) SEM and (d) TEM images of α-Fe2O3 hollow spheres with sheet-like subunits. Adapted from  and reproduced with the permission of the American Chemical Society. (e) Illustration of a two-step electrode design consisting the electrochemically assisted template growth of Cu nanorods onto a current collector followed by the electrochemical plating of Fe3O4.
Liu et al. Nanoscale Research Letters 2012 7:149 doi:10.1186/1556-276X-7-149