Controlled Hydrothermal Synthesis of CeO2 Nanoparticles, Their Photocatalytic Activity and Room Temperature Ferromagnetism

CeO2 nanoparticles have been successfully synthesized by hydrothermal method at different temperatures, using Ce(NO3)3 · 6H2O as the cerium source and CO(NH2)2 as the precipitant. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectrometry, ultraviolet–visible (UV–Vis) spectroscopy and magnetization measurements were used to characterize the samples. The results show that with the increase in synthesis temperatures, the crystallite size increases and the dislocation density decreases. XPS and Raman spectra reflect the presence of oxygen vacancies and Ce3+ ions. All the samples indicate a high UV–Vis light absorption. The photocatalytic activity decreases with the increase in synthesis temperatures, which can be attributed to the energy gap and grain size of the nanoparticles. Magnetization measurements revealed that all the samples show room temperature ferromagnetism (RTMF) which can be attributed to the effects of the oxygen vacancies and Ce3+ ions.