<p>This work introduces innovative Bi₂O₃-ZnO/TiO₂ (BZT) composite photocatalysts, developed via a simple electrospinning technique. The incorporation of Zn²⁺ and Bi³⁺ ions was confirmed through high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). XPS analysis confirmed the presence of Zn and Bi elements on the surface of TiO₂ nanofibers, with oxidation states of + II and + III, respectively. The band gaps, estimated through the Kubelka–Munk function and ultraviolet-visible diffuse reflectance spectroscopy, decreased from 3.18&#xa0;eV for pristine TiO₂ to 2.9&#xa0;eV for the 1%Bi₂O₃-ZnO/TiO₂ (1BZT) composites, resulting in improved light-harvesting capabilities. Photocatalytic performance studies, particularly methylene blue degradation under visible light, revealed notable improvements for Bi₂O₃-ZnO/TiO₂ systems compared to ZnO/TiO₂ and TiO₂. The 1%Bi₂O₃-ZnO/TiO₂ heterostructure was found as efficient photocatalyst with 98% photodegradation of MB. The maximum rate constant, 0.0234&#xa0;min^− 1, was observed for 1BZT nanofibers, which was 4.97 and 16.7 times greater than those of ZnO/TiO₂ and TiO₂, respectively. This enhancement highlights the synergistic effect between Zn²⁺ and Bi³⁺, alongside the enhanced visible light absorption by Bi³⁺, which collectively elevated the photocatalytic efficiency. The heterojunction formed among Bi³⁺, Zn²⁺, and Ti⁴⁺ significantly facilitated the separation of photogenerated charge carriers, which is essential for high photocatalytic efficiency. Quenching experiments confirmed the important roles in the photocatalytic degradation of MB were played by ^•OH and ^•O⁻ ₂ rather than the h⁺ radical under sun light. The 1%Bi₂O₃-ZnO/TiO₂ photocatalyst exhibited the highest level of activity and excellent reusability, retaining its photocatalytic performance over multiple cycles.</p> Graphical abstract <p></p>