Dual-functional CuO/ZrO2/Al2O3 nanocomposite with tailored p–n heterojunction interfaces for enhanced dye degradation and antimicrobial efficiency

A highly efficient CuO/ZrO 2 /Al 2 O 3 ternary nanocomposite was synthesized using a green and cost-effective electrochemical method. The crystallinity, morphology, elemental composition, surface adsorption (BET), optical, catalytic and biological properties of the nanocomposite was systematically characterized using advanced analytical techniques. XRD analysis confirmed the presence of distinct peaks corresponding to CuO, ZrO 2 , and Al 2 O 3 , indicating the successful formation of a visible-light-active catalyst. SEM images revealed strong interfacial interactions between CuO and ZrO 2 integrated within the porous, high-surface-area structure of Al 2 O 3 , UV-Visible and DRS analysis determined the band gap energy to be 2.5 eV. The nanocomposite demonstrated excellent photocatalytic efficiency in degrading Indigo Carmine (IC) dye, achieving up to 95% removal. The high surface area of Al 2 O 3 (195 m²/g) facilitated dye adsorption, while the CuO– ZrO 2 heterojunction enhanced charge separation: sunlight-excited electrons from p-type CuO were transferred to n-type ZrO 2 reducing recombination. Additionally, the nanocomposite exhibited significant antimicrobial activity against various bacterial and fungal strains, outperforming standard references. The novelty of this work lies in the green electrochemical synthesis of a CuO/ZrO₂/Al₂O₃ ternary heterojunction photocatalyst that uniquely combines high surface area, efficient charge separation, and visible-light activity, enabling dual photocatalytic and antimicrobial functionality. Electrochemical Synthesis of CuO/ZrO 2 /Al 2 O 3 nanocomposite and its applications on Photocatalytic degradation of Indigo Carmine (IC) and Antimicrobial Efficiency • CuO/ZrO₂/Al₂O₃ ternary nanocomposite synthesized via green electrochemical route. • UV–Vis and DRS analyses revealed a 2.5 eV band gap suitable for visible-light activity. • Porous Al₂O₃ (195 m²/g) enhanced dye adsorption and interfacial charge transfer. • p–n CuO–ZrO₂ heterojunction improved charge separation and photocatalytic efficiency. • Exhibited dual dye degradation (95%) and strong antibacterial/antifungal activity.