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A series of Y³⁺, Pr³⁺, Er³⁺ and Eu³⁺ modified TiO₂ photocatalysts were obtained via sol–gel (SG) and hydrothermal (HT) methods. Samples prepared this way were characterized by X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), scanning transmission microscopy (STEM), BET surface area method and luminescence spectroscopy. The photocatalytic activity of the synthesized samples was evaluated by the degradation of phenol in aqueous solution under visible and ultraviolet light irradiations. Phenol in aqueous solutions was successfully decomposed under visible light (λ > 420 nm) using TiO₂ modified with RE ions. Luminescence properties of the samples as well as XRD and XPS analyses, indicate that RE are rather in the form of their oxides than in the form of cations in the crystal structure of TiO₂. Photocatalysts prepared by SG method …