Photocatalytic, Antioxidant, Energy Storage, and Sensing Applications of rGO Loaded MnO 2 Nanoparticles
Leelavathi P., Venkatalakshmi V., Mylarappa M., Chandruvasan S., Prasanna Kumar S. G.A reduced graphene oxide/manganese dioxide (rGO/MnO 2 ) was prepared via a reflux method. MnO 2 was prepared by the combustion method using neem leaf extract as a biogenic fuel. The materials were characterized using X‐ray diffraction, Brunauer–Emmett–Teller, transmission electron microscopy, high‐resolution transmission electron microscopy, selected area electron diffraction, EDS, XPS, UV–vis, and photoluminescence spectroscopy. The rGO/MnO 2 exhibited outstanding photocatalytic degradation of methyl violet (MV), achieving ~99.21% removal within 70 min under UV irradiation. The radical scavenging assays demonstrated markedly improved antioxidant activity for rGO/MnO 2 , with a half‐maximal inhibitory concentration (IC 50 ) of 186.77 μL/μg compared to rGO and MnO 2 . Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) revealed a specific capacitance of 132.71 F/g for the composite electrode, nearly double the performance of bare MnO 2 . The electrode also demonstrated superior electrochemical sensing toward Hg 2+ and Cr 2+ metal ions, with lower limits of detection (LOD: 5.94 and 12.42 μM). These results collectively establish rGO/MnO 2 as a nanocomposite with strong potential for environmental and energy storage studies.