Pd@Bi₂Ru₂O₇/BiVO₄ Z‑Scheme Heterojunction Nanocomposite Photocatalyst for the Degradation of Trichloroethylene

Photocatalytic degradation of chlorinated persistent organic pollutants is a very challenging process due to the high redox potential of the C–Cl bond that requires wide band gap catalysts that are activated under UV light. Designing a Z-scheme heterojunction between visible light-activated metal oxides with compatible band gaps enables these redox potentials. Herein, we report the design of a pyrochlore/Aurivillius Z-scheme heterojunction to enhance the photocatalytic activity of BiVO₄ for the degradation of trichloroethylene. We prepared Bi₂Ru₂O₇/BiVO₄ heterostructured photocatalysts by a controlled hydrothermal approach. Upon optimizing the Bi₂Ru₂O₇ ratio to 1.0 wt %, the heterostructured photocatalyst demonstrated enhanced activity in the degradation of trichloroethylene (TCE) under simulated sunlight irradiation compared to bare BiVO₄ and Bi₂Ru₂O₇, respectively. Decorating the surface of the catalyst with palladium nanodomains to create the Pd@Bi₂Ru₂O₇/BiVO₄ nanocomposite showed a substantial increase in the photocatalytic degradation of TCE. The material characterization indicated that the architecture of the material provides a synergy of enhancing the redox potential of the photocatalyst and improving the charge carrier dynamics. Furthermore, the photoelectrochemical characterization confirmed that the dual heterojunctions in the Pd@Bi₂Ru₂O₇/BiVO₄ nanocomposite resulted in improved interfacial charge carrier transfer and enhanced the electron/hole separation efficiency compared to the nonpalladized catalysts. This work provides a promising approach for band gap engineering of visible light photocatalysts for the degradation of halogenated persistent organic pollutants.