Fluorine-doped nanocrystalline ZnO powders prepared via microwave irradiation route as effective materials for photocatalyst

摘要

In this report, we have successfully synthesized nanocrystalline pure and F doped ZnO prepared by one-step microwave irradiation method without using any post annealing treatment. The effect of F dopant on structural, morphological and optical properties were systematically investigated by using powder X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Raman spectra, UV-Vis absorption spectra and photoluminescence spectra analysis. XRD results reveals that both pristine and F doped ZnO had a hexagonal wurtzite type structure and the results are in good agreement with standard JCPDS data (card no. 36-1451). FESEM images showed that random platelets morphology with average diameter around 50-35 nm. A considerable red-shift in the absorption edge and decreasing the band gap of pure ZnO (3.32-3.12 eV) was confirmed though UV-Vis spectra. The defect in crystal and oxygen vacancy was analyzed through PL spectra analysis. The photocatalytic activities of the catalyst powders were evaluated by photocatalytic degradation of methyl violet (MV) and rhodamine B (RhB) and the results showed that the doping of F into ZnO nanoparticles could enhance photocatalytic activity compared to the undoped ZnO nanoparticles, this could be due to reduction of band gap and superior textural properties. The improved photocatalytic mechanism by F doping was also discussed in detail.