Co-/Cu-co-doped ZnO nanorods are synthesized by electrochemical deposition to investigate the effect of co-doping on their structural, optical, electronic, and electrochemical properties. XRD, Raman, SEM, and photoluminescence analyses reveal that Co/Cu incorporation modifies the ZnO lattice, increases defect-related states, and reduces the band gap from 3.11 to 2.15 eV. Density functional theory calculations further show that Co 3d and Cu 3d states appear near the Fermi level and contribute to the observed band-gap narrowing. Electrochemical measurements indicate that the co-doped nanorods exhibit the lowest charge-transfer resistance and the highest areal capacitance among the samples studied. Together, these results show that Co/Cu co-doping improves charge-transfer kinetics in ZnO nanorods and highlights co-doping as an effective strategy for tuning oxide electrodes for energy-storage applications.

In the present work, an essential advance in the preparation of novel nanocomposites based on functionalized V₂O₅ nanostructures with reduced graphene oxide by hydrothermal method, which has great potential for use in photocatalytic processes related to environmental remediation. XRD analysis confirmed V₂O₅ in an orthorhombic structure. SEM images showed transparent RGO layers well anchored onto the surface of the V₂O₅ with a homogeneous distribution. Raman spectroscopy further explained the hybridization and interaction between the components. The photocatalytic activity of Rhodamine-B in aqueous solutions has been studied upon irradiation with visible light. A high RhB degradation was obtained using the V₂O₅/RGO photocatalyst (82 %), compared to the degradation obtained with only V₂O₅ (60 %). First-principles Density Functional Theory (DFT) simulations reveal a strong interaction between V₂O₅ molecules and graphene surfaces, with an adsorption energy of −1.673 eV and a significant charge transfer of 0.367 e− to RGO. This interaction modifies the electronic structure, creating semi-metallic behavior near the Fermi level and enhancing catalytic activity through improved charge carrier dynamics and active sites for photocatalytic applications.