Synergistically enhanced photoelectrocatalytic degradation of ciprofloxacin via oxygen vacancies and internal electric field on a NiSe2/WO3 photoanode†

This study presents the in situ deposition of nickel selenide (NiSe₂) on tungsten trioxide (WO₃) nanorods to enhance the photoelectrocatalytic degradation of organic pollutants in water. The synthesis involves integrating nickel selenide (NiSe₂) and tungsten trioxide (WO₃) nanorod to form a heterojunction, utilizing a facile in situ growth method. The resulting NiSe₂/WO₃ heterojunction exhibits enhanced photocatalytic properties attributed to efficient charge separation, improved charge transfer dynamics, and synergistic catalytic activity created by an internal electric field and oxygen vacancy. The heterojunction demonstrates remarkable performance in the degradation of ciprofloxacin under visible light irradiation. Under optimum conditions, the photodegradation of ciprofloxacin reached 89% (0.0179 min⁻¹) compared to pristine WO₃, which only achieved 48% (0.0069 min⁻¹) under the same conditions. The study systematically investigates the structural and morphological characteristics of the NiSe₂/WO₃ heterojunction and elucidates its superior photocatalytic efficacy through comprehensive experimental analyses. The primary reactive species responsible for CIP degradation were identified as photogenerated h⁺ and ˙OH. The successful development of the NiSe₂/WO₃ heterojunction holds significant promise for advancing environmentally sustainable technologies in water treatment and pollution remediation.