engleski

ENHANCEMENT OF SOLAR DRIVEN DEGRADATION OF CIPROFLOXACIN BY PHOTODEPOSITED Ag ONTO ISO-TYPE HOMOJUNCTION BiVO4 SURFACE

BiVO4 has attracted attention of researchers as one of the promising candidates for visible-light photocatalysis due to its suitable bandgap (≈2.4 eV) and appropriate band structure for the water oxidation. However, the high recombination rate of photo-generated electron-hole pairs as well as short diffusion of charge carries may lead to low photocatalytic efficiency of BiVO4. These limitations may be overcome employing various strategies, including a design of iso-type homojunction, i.e. a junction between two different crystal phases of the same semiconducting material. Such structure can effectively suppress the charge recombination process improving the photocatalytic activity. In this study an iso-type homojunction (monoclinic- tetragonal) BiVO4 material was synthesized and then modified employing photodeposition technique using different amounts of Ag nanoparticles. The as-prepared Ag-BiVO4 has been characterized using SEM, XRD, FTIR, BET, and UV-vis spectra. The impact of Ag nanoparticles on the photoelectrochemical activity of BiVO4 has been systematically evaluated. In addition, electrochemical impedance spectroscopy (EIS) has conducted for the semiconductor/electrolyte interface. The results revealed that the charge transfer resistance decreased under illumination for all as-prepared materials, and Ag-BiVO4 exhibited smaller charge transfer resistance compared to pristine iso-type homojunction BiVO4 material. The photocatalytic activity of as- prepared materials was examined by monitoring the degradation of ciprofloxacin (CIP) as a model organic contaminant under solar irradiation within different pH range (4 to 8) employing Ag-BiVO4 with different Ag content photo-deposited (1 to 15%) and concentration of H2O2 (5 to 30 times the concentration of CIP) and compared to that of pristine iso-type homojunction BiVO4.

BiVO4 ; photodeposition ; solar photocatalysis ; ciprofloxacine ; silver nanoparicles

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