Effect of co-doping on the optical, magnetic and photocatalytic properties of the Gd modified BiFeO₃

Gd doped, and (Gd, Sm), (Gd, La) co-doped BiFeO₃ particles are synthesized by solvothermal method. XRD pattern analysis confirms rhombohedral structure of all the samples. Absorbance spectra reveal bands corresponding to charge transfer of Bi–O, and Fe–O and Fe d–d transitions. The band gap of the co-doped BiFeO₃ samples is found to be less than Gd-doped sample. Photoluminescence spectra of all the samples show transition peaks in the visible region upon excitation at 325 and 365 nm. The magnetization increases for the co-doped samples and Sm co-doped sample exhibits an enhanced coercivity. Photocatalytic tests are carried out at room temperature for the degradation of methylene blue dye in the presence of catalyst and H₂O₂ at pH value 2. 24. Sm co-doped sample shows better photocatalytic activity compared to La codoped sample. The main species for the degradation of dye is found by introducing the scavengers in the reaction. The possible reaction mechanism for the degradation of methylene blue is explained.