قادر حسین زاده

In the current work with innovative combination of sonochemical method with freeze-drying technique graphene/Pd-doped TiO2 nanocomposite was successfully synthesized which has high photocatalytic performance for degradation of Remazol navy blue a textile azo-dye under visible-light radiation. In the designed method, the ultrasound waves were used for dispersion of the Pd-doped TiO2 nanospheres between the graphene layers, which subsequent quick freezing of the obtained suspension by liquid N2 results in the fixing of the positions of the Pd-doped TiO2 nanospheres and the good dispersion of the graphene sheets in the nanocomposite. According to the obtained results, the freeze-dried sample has higher photocurrent, surface area and photocatalytic performance than the conventional dried one. All of these results are related to the best distribution of the graphene layers in the nanocomposite structure. Fast freezing of the graphene/nanoparticles suspension prevents from the stacking (due to the π-stacking interactions) and aggregation of graphene layers during drying, and results in the well distribution of graphene in the final nanocomposite.