Enhanced crystallographic and physicochemical properties of chromium-embedded ZnO nanoparticles

Abstract

Zinc oxide (ZnO) nanoparticles (NPs) have been of growing interest due to their scientific and technological importance. The physicochemical properties of these NPs can be tailored by doping with different transition metals. In this study, Pure ZnO and Chromium (Cr) doped ZnO [Zn0.5-xCrxO (x = 0.02, 0.04, and 0.06 M)] NPs have been prepared by the chemical combustion method. The influence of Cr doping on the physicochemical properties of ZnO NPs was examined using XRD, FTIR, Raman, SEM, UV–visible absorption, and ZP/PSA data. The average crystallite size of as-synthesized pure ZnO (PZ), calcinated ZnO (CZ), Zn0.48Cr0.02O (ZC2), Zn0.46Cr0.04O (ZC4) and Zn0.44Cr0.06O (ZC6) samples are found to be 55, 59, 43, 39, and 34 nm respectively, evident by XRD. Increasing Cr doping reduces average crystallite size in ZnO due to lattice distortion by Cr3+ ions. FTIR spectroscopy confirms Cr presence in Zn0.5-xCrxO NPs, verifying ZnO formation. The size confinement effect on the optical bandgap (Eg) due to the effect of Cr doping is corroborated by UV-visible absorption studies. The Tauc method determined an increased Eg in Zn0.5-xCrxO NPs with higher Cr doping concentrations, attributed to reduced particle size which is also evident by XRD and SEM. Zeta potential (ZP) values endorse that the synthesized ZnO and Zn0.5-xCrxO NPs have good colloidal stability. Zn0.5-xCrxO NPs exhibited enhanced physicochemical properties than the ZnO NPs which is a notable feature of nanomaterials.

Keywords

• ZnO
• Chromium
• Nanoparticles
• Physicochemical properties
• Microwave