A General Synthesis Strategy for Hierarchical Porous Metal Oxide Hollow Spheres

Figure 2

SEM photographs of carbon spheres prepared by adding different kinds and amounts of the surfactants. (a) 0.005 mol/L NH₃H₂O; (b) 0.015 mol/L NH₃H₂O; (c) 0.005 mol/L CTAB; (d) 0.015 mol/L CTAB.

(a)

(b)

(c)

(d)