Photocatalytic-Fenton synergistic degradation of pollutants in wastewater is considered a promising technology for environmental treatment. Herein, FeOOH quantum dots decorated La-doped Bi4O5I2 hybrids were prepared using an in-situ deposition strategy and applied for the removal of 2,4-dinitrophenylhydrazine. The FeOOH-1/La-10-Bi4O5I2 sample exhibits the highest catalytic activity in degradation experiments, eliminating 93.8 % of 2,4-dinitrophenylhydrazine within 30 min at a reaction rate constant of 0.117 min(-1). In addition, the impacts of several operational parameters on the catalytic activity were comprehensively examined, including H2O2 concentration, catalyst dosage, reaction solution pH and co-existing ions. In degradation process of 2,4-dinitrophenylhydrazine, the major reactive oxygen species are center dot OH and center dot O-2(-), with center dot OH generated by Fenton reaction. Optical property characterization, cyclic voltammetry tests, and photoelectrochemical measurements confirmed that the FeOOH-1/La-10-Bi4O5I2 composite has excellent light absorption capacity, abundant active centers, and excellent carrier separation efficiency. Finally, the degradation mechanism of FeOOH-1/La-10-Bi4O5I2 composites for 2,4-dinitrophenylhydrazine is rationally discussed based on experimental and theoretical calculations. This study presents a fresh design idea for developing bismuth oxyhalide-based composites with high activity.
