https://doi.org/10.1007/s10800-025-02426-7
(Accepted October 2025, Published Dec 2025)
The improper management of industrial by-products has become a pressing global issue, posing serious risks to both environmental sustainability and public health. Safeguarding water bodies from harmful contaminants is imperative to preserve ecological balance and to ensure the well-being of life on Earth. The present study demonstrated a highly efficient approach for degrading toxic organic dyes – Methylene Blue, Methyl Orange, Congo Red, and their mixture, through photocatalysis using copper-incorporated zinc oxide nanostructures. The nanostructured photocatalysts were synthesized directly on zinc foil via a straightforward and scalable electrochemical anodization method. The research highlighted the crucial role of optimizing both the copper doping duration and the pH of dye solutions to enhance photocatalytic performance. The superior efficiency of copper-incorporated zinc oxide nanostructures was attributed to the Cu2+/Cu1⁺ redox couple, which acted as an effective electron trap, minimizing electron-hole recombination and promoting catalytic activity. Additionally, copper incorporation led to a notable reduction in the optical band gap, enhancing visible light absorption. The pH-dependent behaviour of the photocatalytic process was linked to the zeta potential of the catalyst and an optimal pH range was identified for the maximum degradation of each dye. Comprehensive structural, optical, compositional, electrochemical impedance and Mott-Schottky analyses further elucidated the mechanisms behind the improved performance. The work underscored the remarkable potential of anodized copper-incorporated zinc oxide nanostructures as highly efficient photocatalysts for the treatment of wastewater containing various dye pollutants, offering a promising pathway towards sustainable environmental remediation.
