Synthesis and Electrochemical Characterization of a Novel Carbon Quantum Dot/Polyaniline/Iron Oxide (CQDs/PANI/Fe₃O₄) Nanocomposite for High-Efficiency Electrode Applications

In this study, a novel composite material combining Iron oxide and carbon quantum dots (CQDs, Fe₃O₄) with PANI was synthesized via a straightforward one-pot hydrothermal method, employing Iron sulfate, PANI and onion peels as the carbon source. The pursuit of an affordable, highly capable electrode material is useful for a variety of next-generation applications. The composite CQDs/PANI/Fe₃O₄ (PF-CDs) was analyzed using various techniques, including FTIR, XRD, SEM, TEM, and UV–vis spectroscopy. The analyses confirmed the presence of functional groups, crystalline structure of CQDs and Fe₃O₄ on the PANI surface, resulting in a well-formed nanocomposite with an average particle size of 25.6 nm. SEM images reveals that the rough surface of pure PANI becomes uniformly decorated with CQDs and Fe₃O₄ in the composite. FTIR study indicates that the core structures of CQDs and PANI are maintained in the nanocomposite. The cyclic voltammograms of the PF-CDs composite exhibit an increase in current density as scan rate increases with visible redox peaks around 0.5 V and 0.25 V. Appearance of semi-circle of the nanocomposite in the Nyquist plot further confirms that nanocomposite has minimum charge resistance and are capable of charge and discharge. Chrono charge discharge graph favours the redox cycle capability of the nanocomposite.