Interfacial Engineering of GO-MnO₂ Nanocomposites for Improved Photocatalytic and Electrochemical Performance

Graphene oxide-manganese oxide (GO-MnO₂) nanocomposites were successfully synthesized via a facile, cost-effective one-pot reflux-assisted wet-chemical route to explore their multifunctional photocatalytic and electrochemical properties. Structural, optical, and morphological characterizations using XRD, Raman spectroscopy, FTIR, and FESEM confirmed the effective incorporation of MnO₂ nanostructures within the GO matrix. The intimate interfacial contact between GO sheets and MnO₂ nanoparticles improved dispersion, minimized agglomeration, and facilitated efficient charge transfer pathways. Optical studies revealed a modified band structure and suppressed electron-hole recombination compared to pristine MnO₂. Photocatalytic activity was evaluated against organic dyes- brilliant green (BG), crystal violet (CV), and methylene blue (MB) under visible light, where the nanocomposites exhibited significantly enhanced degradation efficiency and kinetics. The GO-MnO₂ composite with a 1:1 mass ratio achieved maximum photodegradation efficiencies of 96.4% (BG), 93% (CV), and 94% (MB) within 180 min, attributed to synergistic effects of interfacial charge transfer, extended light absorption, and reactive oxygen species generation. Electrochemical performance assessed by cyclic voltammetry demonstrated improved specific capacitance, further highlighting the benefits of GO-MnO₂ integration. Overall, the nanocomposites exhibit superior photocatalytic activity, electrochemical stability, and multifunctionality, accentuating their potential for advanced energy storage applications and sustainable environmental remediation.