Cr doped ZnO nanoparticles as photocatalyst for the degradation of methylene blue dye

Herein, pristine and Cr doped ZnO nanoparticles (NPs) were synthesized using hydrothermal method and were used as a photocatalyst for the degradation of methylene blue (MB) dye under natural sunlight. Rietveld refinement of the X-ray Diffraction (XRD) pattern confirmed the hexagonal wurtzite structure whereas the presence of elements along with their orbitals was verified from the XPS survey spectra. Field Emission Scanning Electron Microscopy (FE-SEM) images show a distorted rod-like morphology. Among the prepared nanostructure, Zn0.98Cr0.02O NPs possess the lowest bandgap energy due to the presence of optically active sub-levels within the bandgap region. The photoluminescent (PL) spectra were taken with 325 nm as the excitation wavelength with emission peaks in the visible region. The enhanced photocatalytic dye degradation efficiency demonstrated by Zn0.98Cr0.02O under visible light was attributed to the presence of defects in lattice, leads to the reduction electron-hole recombination rate. These features make the prepared nanoparticles as an excellent candidate for applications relating to a number of environmental issues.