Pr-doped Bi4Ti3O12 nanoflowers with built-in Pr4+/Pr3+ redox centers for enhanced photocatalytic degradation of organic pollutants

Wastewater containing organic pollutants poses significant risks to both the natural environment and human health, highlighting the urgent need for developing efficient photocatalytic materials. In this study, Pr-doped Bi 4 Ti 3 O 12 nanoflowers with different doping concentrations were synthesized by a one-step hydrothermal method. Density functional theory (DFT) calculations combined with experimental characterization revealed that the introduction of Pr 4f energy levels creates intermediate states within the bandgap, which act as electron trapping centers and prolong the carrier lifetime. Experimental results demonstrated that the 15.5% Pr/Bi 4 Ti 3 O 12 catalyst exhibited the optimal photocatalytic activity for ciprofloxacin degradation, achieving a removal rate of 89.41% within 60 min. Mechanistic investigations revealed that the coexistence of Pr 4+ and Pr 3+ oxidation states facilitates the conversion of O 2 into superoxide radicals (·O 2 − ), which function as one of the predominant reactive species in the catalytic cycle and are responsible for the enhanced photocatalytic degradation efficiency of the material. As a result, Pr doping significantly improves the photocatalytic performance of the catalyst. This work provides further insight into the underlying mechanism of rare-earth doping in photocatalysts.