An unexpected phase transformation of ceria nanoparticles in aqueous media. Issue 3 (8th February 2019)

• Record Type: Journal Article
• Authors: Kuchibhatla, Satyanarayana V.N.T.; Karakoti, Ajay S.; Vasdekis, Andreas E.; Windisch, Charles F.; Seal, Sudipta; Thevuthasan, Suntharampillai; Baer, Donald R.
• Is Part Of: Journal of materials research. Volume 34:Issue 3(2019)
• Page Start: 465
• Page End: 473
• Publication Date: 2019-02-08
• Subjects: nanostructure, -- Raman spectroscopy, -- X-ray diffraction (XRD); Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1557/jmr.2018.490
• Languages: English
• ISSNs: 0884-2914

Abstract

Abstract: Abstract : Cerium oxide nanoparticles (CNPs) are of significant interest to the scientific community due to their widespread applications in a variety of fields. It is proposed that size-dependent variations in the extent of Ce 3+ and Ce 4+ oxidation states of cerium in CNPs determine the performance of CNPs in application environments. To obtain greater molecular and structural understanding of chemical state transformations previously reported for ceria of ≈3 nm nanoparticles (CNPs) in response to changing ambient conditions, micro-XRD and Raman measurements were carried out for various solution conditions. The particles were observed to undergo a reversible transformation from a defective ceria structure to a non-ceria amorphous oxyhydroxide/peroxide phase in response to the addition of 30% hydrogen peroxide. For CNPs made up of ∼8 nm crystallites, a partial transformation was observed, and no transformation was observed for CNPs made up of ∼40 nm crystallites. This observation of differences in size-dependent transition behavior may help explain the benefits of using smaller CNPs in applications requiring regenerative property.