Structural and topographic study of ceria nanoparticles prepared via different techniques

• Nano-crystalline ceria was obtained using 4 different techniques.
• Oleic acid as a surfactant results in (2 nm) particles and surface area (314 m2/g).
• The surfactant and dispersing media control the formation and morphology.

Nano-crystalline ceria was synthesized using four different techniques. The oleic acid was used as a surfactant in the first technique while Polysorbate 80 (Tween 80) was used instead in the third. On the other hand, the other two techniques were carried out in the absence of any surfactant. The first technique produced samples characterized by the smallest crystallite size (2.8 nm (XRD)), and the lowest hydrodynamic diameter (DLS). Also, if the powder of these samples was dispersed in toluene, its nanoparticles would appear in high agglomerated form in (TEM) and (AFM) photographic images. Accordingly, these samples are suitable to be used as a catalytic agent. Moreover, the results revealed that, the samples prepared in the presence of Tween 80 as a surfactant are recommended to be applied in biological fields. These samples are characterized by small crystallite size 6 nm (XRD) and high surface area (BET). They further produced completely free particles without agglomeration when their powder was dispersed in water. The results confirmed also that, the particle size measurements using (UV–Vis) are greater by about 0.34% than the corresponding values calculated from XRD and BET data. This may be attributed to the significant role of the dispersive medium. X-ray photoelectron spectroscopy (XPS) spectrum confirmed the reverse linear proportionality between the percentage ratio of Ce3+/Ce4+ and the particle size of the investigated samples.

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