Band Gap‐Tuned rGO/MnO 2 /CuO/ZnO Nanocomposites for Improved UV‐Assisted Photocatalytic Dye Degradation: Theoretical and Experimental Study

Abstract

A novel rGO‐based quaternary nanocomposite (NC), CuO/MnO 2 /ZnO@rGO (CMZ@rGO), was synthesized via a facile approach and characterized using x‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emissive scanning electron microscopy (FESEM), energy‐dispersive x‐ray spectroscopy (EDX), elemental mapping analysis. The optical band gap energy confirms effective band gap tuning, assisted by the synergistic integration of the multicomponent metal oxide system with the rGO matrix. The degradation of MB under UV irradiation was used to systematically assess the photocatalytic efficacy of NCs. A consistent and regulated degrading pathway shown 90.9% degradation efficiency in 180 min. The reaction kinetics were well‐described by a pseudo‐first‐order kinetic model. The NC's inhibitive capabilities were discovered in gravimetric anticorrosion investigation in HCl media. NCs expands its applications beyond photocatalysis. MD simulations confirmed the stable adsorption of MB dye molecules on the CMZ@rGO NCs through strong π–π stacking, electrostatic, and coordination interactions. The RDF and Fukui function analyses confirm significant interfacial charge transfer and strong binding affinity between MB and the active metal oxide sites. Together, these results show that the produced quaternary NCs has great potential as a high‐performing, multipurpose material for the treatment of wastewater and related environmental applications.