Electrochemical study of cerium and iron doped MoO3 nanoparticles showing potential for supercapacitor application

Abstract

This study presents the synthesis and comprehensive characterization of undoped MoO3 and its cerium (Ce) and iron (Fe) doped counterparts via hydrothermal route, with a 5 % doping concentration. Structural analysis by X-ray diffraction confirmed the formation of MoO3 with successful doping. UV–vis spectroscopy demonstrated tunable optical properties, with band gap energies of 2.3 eV, 2.0 eV, and 2.8 eV for undoped, Ce-doped and Fe-doped MoO3 respectively. Morphological investigation using scanning electron microscopy revealed distinct nanostructures, including nanorods, agglomerated nanoparticles, and pebble-like structures, influenced by doping. Electrochemical characterization through cyclic voltammetry and potentio electrochemical impedance spectroscopy showcased superior charge storage capacity in Fe-doped MoO3, attributed to the largest area under the curve in cyclic voltammograms. Fe-doped MoO3 exhibited lowest resistance as compared to undoped and Ce doped MoO3, suggesting enhanced conductivity. The presence of a Warburg element in all samples indicated diffusion-limited electrochemical processes. The variation of log (scan rate) with log (current) revealed distinct charge transfer mechanisms, with near-unity slopes for doped samples and a slope near 0.5 for undoped MoO3. These findings provide insights into the tunable properties of doped MoO3, offering potential applications in various electrochemical devices.