Effect of synthesis parameters on tuning of phase and shape of hierarchical iron oxides and selective application as supercapacitor.

The synthetic strategy for iron oxides with diverse superstructures has become one of the most promising researches due to their advance and synergistic application in energy and environment field. Self-assembling of nanostructure to structural hierarchy in general enhances mass transportation, reducing resistance to diffusion, and high surface areas for adsorption and electrochemical reaction, and thus much effort has been devoted to the exploration of various novel synthesis schemes for high-throughput synthesis processes with a choice of starting materials. In this strategy, we utilize metal-organic solvent solutions as the starting material for synthesizing functional hierarchical iron oxide materials without further addition of base for hydrolysis reactions. The process is templates/surfactant less which makes the process simple without intact of other impurities in desired structure. The agglomerations of the particles are also controlled due to acidic pH condition adopted during synthesis. All the experiments were done at a moderate temperature (~ < 100 °C) with a variation of time and concentration. The reaction parameters are optimized to get uniform and highly dispersed flower or spindle-shaped 3D hierarchical goethite phase and thereof we evaluate the electrochemical capacitance using cyclic voltammetry technique. One of the pure iron oxide samples shows specific capacitance value of 243.2 Fg⁻¹ and exhibited 26 Wh Kg⁻¹ energy density at 0.5 Ag⁻¹ current density. [ABSTRACT FROM AUTHOR]