Synthesis and dielectric properties of Cr-substituted CeO_2 nanoparticles

摘要

Chromium doped ceria nanoparticles have been synthesized by using a novel solution combustion method with chromium nitrate hexahydrate as oxidizers and glycine as a fuel. The main objective of the present study is to find the effect of chromium on structural, optical, dielectric properties and ac- conductivity of cerium oxide nanoparticles (CeO~(2)NPs). The prepared samples were characterized by various physicochemical techniques such as UV–Vis absorption spectra, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDS) analysis. The powder XRD patterns confirm the cubic fluorite structure of CeO~(2)NPs. The UV–Vis absorption spectra showed that the doping causes the red shift of absorption peaks. The optical band gap of all samples has been measured by Tauc plot, which is found to be decreases with chromium concentration. The uniform shaped NPs with the range of ~ 20 nm is observed by FESEM images. EDS analysis confirms the expected elemental composition of Ce~(1−x)Cr~(x)O~(2)NPs. The dielectric constant ɛ′, dielectric loss factor (tanδ) and AC conductivity of the samples were studied as function of frequency range from 20 Hz to 3 MHz and found to be decreases with increasing the chromium content.