Figure 1

Scanning electron microscope images of the composite prepared at FeCl₃ concentrations of 0.01–0.10 M: (a) 0.01 M, (b) 0.02 M, (c) 0.03 M, (d) 0.04 M, (e) 0.05 M and (f) 0.10 M. (g) Transmission electron microscopy of CNT film-Fe₃O₄-0.04 M-graphene. (h) The selected-area electron diffraction pattern of Fe₃O₄ nanoparticle.