Facile immobilization of iron on carbon nanospheres using organometallic-complex for supercapacitor applications

In recent years electrochemical energy storage solutions such as supercapacitors have emerged as an attractive option. Supercapacitor electrode materials which are carbon-based composites with metal/metal oxide/metal hydroxide show enhanced energy density properties otherwise lacking in purely carbon-based systems. In this work, carbon nanospheres (CNSs) were synthesized using the hydrothermal method with an average diameter of 460 nm. Multiple samples were prepared of iron immobilization on the surface of CNSs by the ultra-sonication process using an organometallic complex, tris-(1,10-phenanthroline)-iron (II) sulfate (Fe-complex). The organo-metallic complex, as well as the synthesized CNS-Fe powders, were characterized using UV-Visible Spectroscopy, FTIR, SEM, and BET surface area analyzer as applicable. FTIR, UV-Visible and EDS results were used to delineate that the amount of Fe-complex immobilized on the CNSs is ranging from partial to complete coverage of the CNSs. The Fe-complex immobilized CNSs demonstrated good applicability for supercapacitor electrode applications. The electrochemical capacitance measurements with a three-electrode setup show that the pseudo capacitance value enhancement was best for CNS samples with a partial surface coverage of Fe-complex.