Novel controlled hydrothermal synthesis of three different CeO_2 nanostructures and their morphology-dependent optical and magnetic properties

摘要

In the work, we explored an efficient synthetic platform to purposefully fabricate CeO2 nanostructures with different morphologies of by controlling the different solution conditions. All the obtained samples were characterized by means of XRD, SEM, TEM, XPS, Raman scattering, UV-Vis, Photoluminescence (PL) spectra and M-H curves. The results show that all the samples have a cubic fluorite structure and the samples synthesized in alkaline, acidic and neutral aqueous solution display nanorodanotube, nano-plate and nano-octahedron structure, respectively. It was also found that there is a red-shifting in the band gap of the obtained material compared to bulk one, which is mainly attributed to the influences of Ce3+ ions, oxygen vacancies and the change of sample morphology. The existence and increase of Ce3+ ions and oxygen defects in the CeO2 samples can lead to a smaller band gap, stronger PL diffraction and elevated ferromagnetism.