A novel sunlight-activated double-shell Cu@Cu2O/SiO2 (m-pCu@Cu2O/SiO2) photocatalyst is presented via a combined precipitation and sol-gel methods with a mesoporous silica outer shell. After applying several characterization techniques on the m-pCu@Cu2O/SiO2, it was tested in the photodegradation of ciprofloxacin (CIP). The experimental results demonstrated a higher photocatalytic activity of the double-shell m-pCu@Cu2O/SiO2 nanophotocatalyst than the core-shell pCu@Cu2O nanophotocatalyst under the sunlight irradiation. When the content of pCu@Cu2O was 30 wt.%, it showed the highest activity. The Cu nanoparticles exhibited the surface plasmonic resonance (SPR) effect which increased the light absorption in the visible region of light. It also caused the rapid separation of the photoexcited e-/h+ pairs. Furthermore, the mesoporous structure of outer shell silica favors the transfer of reactants, resulting in the improved photoactivity performance for the supported pCu@Cu2O catalyst. Central composite design (CCD) based on RSM (response surface methodology) approach was used to optimize four of the most important experimental variables. The photodegraded intermediates were identified by HPLC-Mass.
Keywords: Ciprofloxacin; Double-shell; Mesoporous; Nanophotocatalyst; Plasmonic; Response surface methodology.