Influence of Cr Doping on the Microstructural, Optical and Photocatalytic Properties of ZnO Synthesized by Sol-Gel Method

Nanosized Cr doped ZnO particles were synthesized by facile sol-gel method. The structural, optical and photocatalytic properties of the particles have been investigated by XRD, UV-Vis and FTIR spectroscopy at room temperature for 0%, 0.5%, 1%, 3% and 5% doping concentrations of Cr. X-ray diffraction analysis reveals that the Cr doped ZnO occurs in a single phase polycrystalline nature with wurtzite lattice. The average crystallite size decreases with increase in Cr concentration. The UV-Vis spectra of the nanoparticles indicate decrease in band gap energy upto 3.47 eV for 5% Cr substituion. FTIR results also show the correlation between structural and optical properties of the nanoparticles. The photocatalytic activity of the nanoparticles was investigated by studying the degradation of a dye derivative, Acid Red 17 under UV light source as a function of irradiation time. An increase in the degradtion of the dye was observed from 24.86% to 66.47 % from pure nanosized ZnO to Cr doped ZnO during 70 min of illumination.