A novel strategy, ion diffusion method controlled by ion exchange membrane combining with agar hydrogel template, was reported for the synthesis of Mn₃O₄ nanoparticles without any oxidizing agents. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauere-Emmette-Teller (BET) isotherm were carried out to characterize the structure, morphology, pore size and distribution and specific surface area of the as-prepared nanomaterials. It is shown that the morphology and size of Mn₃O₄ nanoparticles can be controlled by the concentration of agar hydrogel. All the specific capacitances of the Mn₃O₄ samples prepared with agar hydrogel template are much higher than that of Mn₃O₄ prepared without any template agent. The Mn₃O₄ sample prepared at 1.5 g L-1 of agar hydrogel solution exhibits a highest specific capacitance of 183.0 F g-1 at the current density of 0.5 A g-1, which is increased by 293% compared with that of Mn₃O₄ synthesized without any template agent. The results indicate that the ion diffusion method controlled by ion exchange membrane combining with agar hydrogel template is a convenient and effective approach for preparing inorganic nanomaterials.
Keywords: Mn3O4 nanoparticles; agar hydrogel; electrochemical performance; ion diffusion; ion exchange membrane.