Efficient photoelectrocatalysis for dibutyl phthalate degradation and simultaneous hydrogen evolution using an S-scheme F-BiOF/TiO2 nanocones heterojunction

Addressing water pollution and energy shortage simultaneously remains a key environmental challenge, yet conventional water treatment rarely removes pollutants while recovering energy. Phthalate esters (PAEs), a class of toxic and persistent emerging contaminants, urgently require advanced oxidation technologies. Herein, an efficient photoelectrocatalytic (PEC) system was developed based on S-scheme F-BiOF/TiO 2 nanocones (NCs) photoanode for deep degradation of the representative PAEs, dibutyl phthalate (DBP), with simultaneous hydrogen (H 2 ) evolution. BiOF was first loaded onto TiO₂ NCs to form a compact BiOF/TiO₂ interface, and subsequent electrochemical F activation regulated the interfacial electronic structure and strengthened the internal electric field, thereby promoting S-scheme heterojunction directional charge separation. This design retained the strong oxidation ability of BiOF valence-band holes and the reduction ability of TiO₂ conduction-band electrons. Density functional theory (DFT) and spectroscopic analyses confirmed that F activation significantly strengthened the internal electric field and facilitated directional charge separation, thereby boosting PEC performance. Under simulated sunlight irradiation at 0.8 V, the system achieved 96.5% DBP removal and 967.7 μmol/cm 2 H 2 production within 90 min. Notably, the H 2 yield dropped to 559.3 μmol/cm 2 without DBP, demonstrating that anodic pollutant oxidation can promote cathodic H 2 evolution. Fukui-function revealed that the degradation of DBP initiated with preferential attack on its ester group, while HeLa cell assays confirmed decreasing intermediate toxicity. The system also showed robust performance in real wastewater, highlighting its potential for integrated recalcitrant pollutant removal and clean energy recovery.