Sodium periodate-driven one pot iodine doping TiO2 for superior visible-light photocatalytic degradation

Visible light driven photocatalysis offers a sustainable solution for environmental remediation. As a cornerstone photocatalyst, the practical application of TiO 2 is severely constrained by its narrow visible light response range and inefficient charge carrier separation. An innovative one-pot synthesis strategy was developed for preparing a highly active iodine-doped TiO 2 (I-TiO 2 ) visible light photocatalyst, using NaIO 4 ′s dual functionality as simultaneous iodine source and oxidant. Characterization revealed that the successful iodine doping in TiO 2 matrix effectively reduced bandgap energy and suppressed charge carrier recombination, consequently broadening optical absorption range and enhancing visible light responsiveness. The prepared anatase I-TiO 2 exhibited small crystallite of 6.93 nm and high surface area of 222.61 m 2 /g. The optimized I-TiO 2 achieved 99.04 % and 89.65 % degradation efficiency of methylene orange (MO) solution within 10 min and 60 min, while maintaining 92.6 % and 85.1 % after consecutive three recycling tests under simulated sunlight and visible light, respectively, demonstrating its superior photocatalytic activity and stability. Active species trapping experiment and ESR analysis revealed that superoxide radicals (⋅O 2 − ) served as the dominant active species in I-TiO 2 photocatalytic degradation process of MO solution. This work provides new insights into oxidant-assisted doping strategies for designing high-performance visible light photocatalysts.