The pH Influence on the Preparation of Hollow Fe2O3 Spheres by Hydrothermal Method

In this paper Fe2O3 precursor coating on the surface of carbon balls was prepared by hydrothermal method using Fe(NO3)(3)center dot 9H(2)O and glucose as the raw materials. After calcination Fe2O3 hollow sphere could be achieved. The influence of pH value on the preparation of hollow Fe2O3 spheres was studied using XRD and SEM respectively. The results show that the pH value has no effect on the formation of Fe2O3 phase, but has a giant influence on the morphology of the hollow spheres. The Fe2O3 hollow spheres were achieved when the pH value was between 3 and 7. The particles with sheet and block structure form when pH<3 or pH>7. The mechanism was studied, When 3<pH<7.8, the absorption action of Fe(OH)(3) on the carbon balls is changed from the electrostatic interaction to the chemical interaction due to positive zeta potential, which benefits producing homogeneous hollow spheres.