A novel design of porous Cr2O3@ZnO nanocomposites as highly efficient photocatalyst toward degradation of antibiotics: A case study of ciprofloxacin

Abstract

A novel design of porous Cr2O3@ZnO photocatalysts for the first time with high surface area (1690 m2/g) and large pore volume (0.057 cm3/g) has been synthesized for the destruction of ciprofloxacin (CIP) as a case study upon visible light exposure. The complete CIP degradation (100%) was performed within 30 min, and it was promoted 20 times higher than that of pure ZnO. Interestingly, the photodegradation rate of CIP over 3%Cr2O3@ZnO nanocomposite is greater 34 fold than that pure ZnO. The highly enhanced photocatalytic efficiency of the porous Cr2O3@ZnO nanocomposites was explained by constructing porous Cr2O3@ZnO heterojunction system in nanoscale with synergetic effect and reduces light scattering effect and rapid migration of CIP to the active sites. The synthesized Cr2O3@ZnO nanocomposite revealed excellent reusability within five consecutive cycles during the illumination of visible light for a long time. The surface charge transfer over Cr2O3@ZnO nanocomposite was examined by the photoluminescence (PL) and transient photocurrent studies. The photocatalytic mechanism of the porous Cr2O3@ZnO nanocomposites was also discussed. Moreover, based on HPLC/MS analysis, the reaction pathway and fragment intermediates for CIP were investigated in detail during the illumination time. The porous Cr2O3@ZnO nanocomposites photocatalyst has superior potentials for practical antibiotic- photodegradation engineering.