Hydrothermal synthesis of Fe₂O₃ nanoparticles and their electrochemical application

In the present investigation, we report on Iron oxide (α-Fe₂O₃) nanoparticles synthesized by simple hydrothermal method with different reaction times as 6 h (H1) and 8 h (H2) for supercapacitor application. The significance of varying the reaction time on structural, morphological, and vibrational properties of α-Fe₂O₃ was explored. XRD, FTIR, and Raman study affirmed that the products consist of only the rhombohedral phase of α-Fe₂O₃ nanoparticles. SEM image infers that with a change in reaction time the surface morphology of α-Fe₂O₃ changed from spherical to octahedra. The size of nanoparticles reduced with reaction time. XPS spectra again confirmed the growth of α-Fe₂O₃ nanoparticles. The electrochemical characteristics of the fabricated H2 electrode exhibited excellent performance in a 2 M KOH electrolyte solution. The specific capacitance (Cs) achieved from CV and GCD curves were 299.4 F g⁻¹, and 351.3 F g⁻1. The R_ct acquired via electrochemical impedance (EIS) reduced from 11.2 to 9.18 Ω demonstrating the rise in the conductivity of the prepared electrodes. Remarkable capacitance retention of 92% was accomplished, even after 1000 cycles, thus making α-Fe₂O₃ nanoparticles a most promising electrode for the fabrication of energy storage devices.