Core/shell structure with colloidal carbonaceous microspheres as core and nanowhisker-like Ni(OH)(2) as shell was synthesized by a facile precipitation method. NiO hollow spheres with hierarchical nanostructure and amorphous carbon/nickel nanoparticles composites were obtained by heat treatment in air and nitrogen, respectively. Nitrogen adsorption and desorption analysis indicated that these two novel products are both nanoporous materials with high specific surface area and large pore volume.