Efficient abatement of oxytetracycline and simultaneous hydrogen generation via 3D particle electrode-based dynamic adsorption-photoelectrocatalytic oxidation coupling.

Integrating water contaminant control with hydrogen (H2) generation in photoelectrocatalytic (PEC) system offers a promising strategy for sustainable wastewater treatment. However, conventional two-dimensional (2D) PEC systems are often limited by insufficient interfacial active sites and poor mass transfer. Herein, a 3D PEC system was constructed using 1,4-benzenedicarboxylic acid-modified mixed-valence iron oxides (FeOx) supported on activated γ-Al2O3 (FeOx-BDC@Al2O3) particle electrodes to enable dynamic adsorption-PEC oxidation coupling for efficient oxytetracycline (OTC) removal and concurrent H2 generation. Compared with the conventional 2D system, the 3D PEC system achieves 93.2% OTC removal within 2 h. Meanwhile, the H2 production rate reaches 33.6 μmol cm-2∙h-1, which is 2.26 times that of the 2D system. The enhanced performance is attributed to the adsorption enrichment of OTC on FeOx-BDC@Al2O3/electrolyte interface, the improved light-harvesting ability of FeOx-BDC@Al2O3 particles, the accelerated Fe3+/Fe2+ redox cycling, the PEC synergistic generation of reactive species, and the uninterrupted concentration gradient of OTC between the bulk solution and the FeOx-BDC@Al2O3 particle surface, which establishes a continuous dynamic adsorption-PEC oxidation coupling system for efficient OTC abatement and detoxification. This work provides an effective strategy for integrating pollutant enrichment, sustained oxidation, and H2 generation in a 3D PEC system for antibiotic-contaminated water treatment.