Synthesis and characterization of TiO₂/CuS nanocomposite fibers as a visible light-driven photocatalyst

TiO₂/CuS nanocomposites were fabricated by precipitation of nanosized CuS via sonochemical method on electrospun TiO₂ nanofibers, and their structure, chemical bonding states, optical properties, and photocatalytic activity were investigated. In the TiO₂/CuS nanocomposite, the position of the conduction band for CuS was at a more negative than that of TiO; meanwhile, the position of the valence band for CuS was more positive than those for TiO, indicating a heterojunction structure belonging to type-II band alignment. Photocatalytic activity, measured by decomposition of methylene blue under visible-light irradiation (λ > 400 nm) for the TiO₂/CuS nanocomposite, showed a value of 85.94% at 653 nm, which represented an improvement of 52% compared to that for single TiO₂ nanofiber (44.97% at 653 nm). Consequently, the photocatalyst with TiO₂/CuS nanocomposite had excellent photocatalytic activity for methylene blue under visible-light irradiation, which could be explained by the formation of a heterojunction structure and improvement of the surface reaction by increase in surface area.