Agar Hydrogel Template Synthesis of Mn3O4 Nanoparticles through an Ion Diffusion Method Controlled by Ion Exchange Membrane and Electrochemical Performance

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