Figure 2. Characterization of Co₃O₄ superstructure mediated by bacteria-templating.

(a, b), FE-SEM images of uniform, bacteria-supported, hierarchical Co₃O₄ superstructures produced without changing the spherical shape of the original bacteria template. Low- (a) and high-magnification micrographs (b). Inset in (b) shows the morphology of an individually hierarchical, flower-like, porous-Co₃O₄ nanostructure grown on a bacterial template. The scale bar in the inset of (b) represents 200 nm. (c), An enlarged image for one of the anchored areas where the Co₃O₄ nanostructures were attached and grown on the bacterial surface. (d), TG analysis measured in air for the obtained hierarchical, porous-Co₃O₄/bacteria (RT-Co₃O₄, red line) and the original bacteria (Pure Micrococcus, black line). The weight loss was 59.3 and 90.6%, respectively. (e), XRD patterns for the obtained hierarchical, porous-Co₃O₄/bacteria powders. The positions of the peaks were indexed to the Co₃O₄ phase (JCPDS card #42-1467, red line). (f), The N₂ adsorption-desorption isotherm and the pore size distribution curve (the inset in (f)) for the obtained hierarchical, porous-Co₃O₄/bacteria powders.