Construction of CuS/TiO2 nano-tube arrays photoelectrode and its enhanced visible light photoelectrocatalytic decomposition and mechanism of penicillin G

Highlights: • CuS/TiO₂ NTAs photoelectrode was fabricated by electrodeposition process. • CuS/TiO₂ NTAs photoelectrode exhibited superior physicochemical properties. • CuS/TiO₂ NTAs photoelectrode displayed superior PEC performance. • PEC degradation pathways of penicillin G was proposed and confirmed. In this present work, a CuS/TiO₂ nano-tube arrays photoelectrode employed in environment purification was successfully prepared by an anodization process, with galvanostatic electrodeposition strategy as following method. Meanwhile, morphologies and chemical structures of the resulting photoelectrodes were studied by series of measurements. The results indicated that CuS nanoparticles were successfully assembled on the surface of well-ordered TiO₂ nano-tube arrays, which has significantly enhanced the photoelectrocatalyic activity by red-shifting the light absorption to visible region and increasing the photoinduced charge separation efficiency. What's more, when external potential was applied, CuS/TiO₂ nano-tube arrays photoelectrode displayed superior photoelectrocatalyic performance for elimination of penicillin G (99.1%) within 150 min visible light illumination. Moreover, the visible light photoelectrocatalyic degradation pathways of PEN G were proposed based on the HPLC-MS/MS measurements, which included decarboxylation and oxidation of the target organic, and finally mineralization to H₂O, CO₂, NH₄⁺ and NO₃⁻. This study demonstrated that the novel CuS/TiO₂ NTAs photoelectrode showed excellent PEC activity, which had great potential in applications of environmental remediation.