Mixed-phase TiO 2 photocatalysts: Crystalline phase isolation and reconstruction, characterization and photocatalytic activity in the oxidation of 4-chlorophenol from aqueous effluents

•Anatase and rutile were isolated from Degussa (Evonik) P25 by selective dissolution.•TiO2 powders were characterized by XRD, HRTEM, Raman and DR–UV–vis spectroscopies.•First derivative DR–UV–vis spectroscopy was used to calculate the Eg of TiO2 phases.•DR–UV–vis spectroscopy detected the presence of TiO2 impurities in the main phase.•No synergistic effect was observed in the mixed-phase photocatalyts.