Physics

Permanent URI for this community

https://escholar.umt.edu.pk/handle/123456789/10137

Browse

Browsing Physics by Author "ADEELA BASHIR"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Synthesis and characterization of pristine and Sr-doped ZnO nanostructures for methyl green photodegradation application
    (UMT, Lahore, 2021) ADEELA BASHIR
    The present work describes an effective route for degradation and de-colorization of methyl green (MG) dye by pristine and Strontium (Sr) doped Zinc oxide (ZnO) photocatalysts under visible light. The pair of ZnO and Sr-ZnO photocatalysts have been synthesized by the chemical precipitation method. The structural analysis using X-ray diffractometer has experimentally confirmed that both photocatalysts exhibit the hexagonal wurtzite structure, without any additional phase formation in Sr-doped ZnO, in particular. However, interestingly the doping with Sr2+ cation has caused a slight shift in the XRD peaks toward lower diffraction angles, which may be sourced by a slender increase in the lattice parameters. The crystallite size and internal strain for both photocatalysts have been calculated using Williamson-Hall plot. The optical properties of the synthesized photocatalysts have been investigated using UV–vis absorption spectroscopy in the wavelength range ~ 250-800 nm. As observed in Tauc’s plot, the slight decrease from 3.3 to 3.2 eV in band gap energy in case of Sr-doped ZnO may be due to formation of sub-band level between valence and conduction band caused by the impregnation of Sr2+ ions in the ZnO host. The morphological study has also been performed by using FESEM, which indicates nanoflakes (NFs) based surface texture. During the photocatalytic activity study, after 30 minutes irradiation of visible light, ~65.7% and ~84.8% photocatalytic degradation of MG aqueous solution has been achieved for Sr-doped (2 wt.%) and pristine ZnO photocatalyst, respectively. The rate of photocatalytic reaction (K) has been observed to be ~ 0.06399 min-1 for Sr-doped (2 wt.%), whereas nearly half magnitude ~ 0.03403 min-1 has been observed with pristine ZnO, respectively. The better photodegradation activity may be ascribed to the relatively broader optical absorption capability and the enhanced charge separation efficiency of the Sr-doped ZnO photocatalyst.