In this study, Cu⁃doped TiO₂ photocatalysts were prepared by the sol⁃gel method using tetrabutyl titanate as the titanium source and copper(II) chloride dihydrate as the copper source. Their phase composition, morphology, and surface chemical composition were characterized by XRD, SEM, and XPS; photoelectrochemical tests were conducted to investigate the photoelectrocatalytic properties of the materials, and Rhodamine B (RhB) was used as the target pollutant to evaluate their photo⁃Fenton catalytic performance,the mechanism by which Cu doping enhances the photo⁃Fenton activity of TiO₂ was also elucidated. The results show that 5% Cu⁃TiO₂ exhibits the best performance for RhB degradation, with a degradation rate constant 7.0 times that of TiO₂. This enhancement is mainly attributed to Cu doping, which introduces impurity energy levels into TiO₂, significantly narrows the band gap, and extends the photoresponse into the visible⁃light region, thereby improving the photo⁃Fenton catalytic performance.