The Zn and Cu bi-components co-modified ZnO-Cu2O-TiO2 composites with 3DOM structure were constructed via a facile glycol-assisted sol–gel method. The morphology, composition and structure of the prepared samples with five different Cu/Zn mass ratios were characterized by XRD, SEM, XPS, UV–VIS DRS and N2 adsorption–desorption. The results indicate that the oxygen vacancies contents of the as-prepared catalysts are heavily dependent on the Cu/Zn mass ratios. Among the five catalysts, the Zn0.06-Cu0.14 sample shows the highest oxygen vacancies content. These findings reveal that the introduction of a certain proportional ZnO and Cu2O can promote the capturing efficiency of visible light and the charge carrier separation, ultimately resulting in an enhanced photodecoloration performance of MB.