Selective FeOx deposition on BiVO4 (010) Facet: boosting visible-light-driven photo-Fenton degradation of PPCPs

Carbamazepine (CBZ), a typical pharmaceutical and personal care product (PPCP), has an annual global consumption exceeding several thousand tons. Its molecular structure contains symmetrical nitrogen-containing aromatic heterocycles, which resist degradation by conventional biochemical methods, resulting in persistent aquatic pollution. Integrating photocatalytic processes with Fenton reaction provides a targeted approach for its effective elimination from aquatic systems. However, traditional photo-Fenton systems suffer from inefficient Fe 3+ /Fe 2+ redox cycling due to sluggish Fe³⁺ regeneration and rapid recombination of photogenerated charge carriers. To address these challenges, this study designed a facet-engineered BiVO 4 photocatalyst through selective deposition of FeOx nanoparticles on the electron-rich (010) facets of monoclinic BiVO 4 via hydrothermal and photodeposition methods. The optimized FeOx/BiVO 4 composite exhibited exceptional degradation performance for CBZ, achieving a rate constant of 0.317   min -1 , which is 24-fold higher than that of pristine BiVO 4 . Mechanistic investigations revealed that the selective FeOx deposition not only promoted the valence-state transition of Fe 3+ to Fe 2+ but also enhanced charge carrier separation, thereby establishing a sustainable Fe 3+ /Fe 2+ redox cycle. Electron paramagnetic resonance (EPR) analysis and radical quenching experiments further identified hydroxyl radicals (·OH) as the dominant reactive species. This work provides a paradigm for designing efficient photo-Fenton reaction systems through targeted facet engineering, offering broad implications for the remediation of PPCPs.