Cerium oxidation state in ceria nanoparticles studied with X-ray photoelectron spectroscopy and absorption near edge spectroscopy

Zhang, Feng; Wang, Peng; Koberstein, Jeffrey T.; Khalid, Syed; Chan, Siu‐Wai

doi:10.1016/j.susc.2004.05.138

Cited by 537 publications

(363 citation statements)

References 33 publications

Supporting

Mentioning

339

Contrasting

Unclassified

Order By: Relevance

“…3) resulting from the various initial and final states of Ce 3+ and Ce 4+ cations (Table 2). In general, the Ce 3d spectra can be individually deconvoluted into five pairs of 3d 5/2 and 3d 3/2 spin-orbit components (labelled as v and u, respectively) describing the Ce 4+ ↔ Ce 3+ electronic transitions [18][19][20][21][22][23]. According to the literature [18][19][20][21][22][23], the four intense components v (BE ∼ 882.2 eV), u (BE ∼ 900.8 eV), v /// (BE ∼ 898.1 eV), u /// (BE ∼ 916.2 eV) as well as the two weaker components v // (BE ∼ 888.8 eV) and u // (BE ∼ 906.9 eV) can be attributed to Ce 4+ cations.…”

Section: Resultsmentioning

confidence: 99%

“…In general, the Ce 3d spectra can be individually deconvoluted into five pairs of 3d 5/2 and 3d 3/2 spin-orbit components (labelled as v and u, respectively) describing the Ce 4+ ↔ Ce 3+ electronic transitions [18][19][20][21][22][23]. According to the literature [18][19][20][21][22][23], the four intense components v (BE ∼ 882.2 eV), u (BE ∼ 900.8 eV), v /// (BE ∼ 898.1 eV), u /// (BE ∼ 916.2 eV) as well as the two weaker components v // (BE ∼ 888.8 eV) and u // (BE ∼ 906.9 eV) can be attributed to Ce 4+ cations. For Ce 3+ cations, the v / (BE ∼ 885.6 eV) and u / (BE ∼ 903.9 eV) components are more intense, whereas the v 0 (BE ∼ 880.6-881.4 eV) and u 0 (BE ∼ 898.9-899.3 eV) components are noticeably weaker and sometimes their contributions in the Ce 3d spectrum can not be clearly distinguished, in particular at a high concentration of Ce 4+ cations [23,26,30].…”

Section: Resultsmentioning

confidence: 99%

“…X-ray photoelectron spectroscopy (XPS) is the method that allows monitoring changes in the local environment of ions and their oxidations states [17]. The surface chemical states of Ce cations have been explored so far preferably for undoped CeO 2 [18][19][20][21][22][23], CeO 2 -based solid solutions [24][25][26], and composites composed of CeO 2 and transition metals or their oxides [27][28][29][30][31][32][33][34]. It was shown that properties of composite materials (redox properties, formation of surface and bulk oxygen vacancies, oxygen storage and release) can be optimised through the variation of the CeO 2 /Me(Me x O y ) ratios.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Konysheva

Francis

2013

Applied Surface Science

View full text Add to dashboard Cite

Keywords:X-ray photoelectron spectroscopy (XPS) Surface composition Composites with perovskite and fluorite structures Oxidation state of cerium cations Binding energy a b s t r a c t X-ray photoelectron spectroscopy (XPS) has been used to explore the cation rearrangement between the surface and bulk of grains and the surface chemical states of Ce, Mn, Co, Sr, and O ions in the single phase CeO 2 -based solid solutions and in the two phase (100 − x)La 0.6 Sr 0.4 CoO 3 -xCeO 2 (LSCCx) and (100 − x)La 0.8 Sr 0.2 MnO 3 -xCeO 2 (LSMCx) composites. The well-resolved Ce 3d 5/2 and Ce 3d 3/2 spin-orbit components were determined to study the Ce 4+ to Ce 3+ electronic transition at the surface. The surface of the LSCCx and LSMCx (x = 8-40 mol%) composites is depleted in cerium. Both Ce 4+ and Ce 3+ cations were revealed. The surface fraction of Ce 4+ cations increases with the rise in CeO 2 content in both systems, but it is higher by about a factor of two in the LSCC composites. A strong enrichment of the surface by Co cations was observed for the composites LSCCx (x = 8-40 mol%), implying that the presence of cerium could facilitate the Co surface segregation. A slight Sr surface enrichment compared to the nominal stoichiometry was found for La 0.6 Sr 0.4 CoO 3 , CeO 2 -based solid solutions, LSCC57, and LSMCx (x = 10-57) composites. In contrast, the surface of the LSCCx (x = 10-37) composites is slightly depleted in strontium cations. The O 1s spectra of the LSCC and LSMC composites contain several contributions associated with the lattice oxygen related to the phases with the perovskite and fluorite structures as well as with different surface states. Their contributions vary with CeO 2 content and a chemical origin of the transition metal cations on the B-site in the perovskite structure. The Ce 2 (CO 3 ) 3 -based phase seems to exist at the surface of grains and crystallites in the LSCC57 and LSCM composites.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Konysheva

Francis

2013

Applied Surface Science

View full text Add to dashboard Cite

show abstract

“…89 An interesting example of the high spatial resolution that can be achieved with this type of instruments is provided by a recent TEM study of ceria nanoparticles (3-20 nm in diameter) in which EELS spectra are able to resolve between valence states of cerium at the edge in comparison to the center of the particles. 102 Thus, even though as shown in a joint XPS-XANES study this phenomenon is still subject to some debate, 103 such TEM-EELS study nicely show the valence reduction of cerium with decreasing the particle size and the preferential reduction of cerium at the surface of the nanoparticles. 102 In connection with this, TEM images can be also formed with electrons that have lost a specific energy with respect to a determinate energy threshold of the atomic inner shell, giving rise to energy-filtered TEM (EF-TEM).…”

Section: Tem and Stemmentioning

confidence: 95%

Techniques for the Study of the Structural Properties

Rodríguez

Fernández-García

Martı́nez-Arias

et al. 2006

Synthesis, Properties, and Applications of Oxide Nanomaterials

View full text Add to dashboard Cite

“…oxygen vacancy formation, are were expected. It is well known that, in the case of the chlorinated catalyst, an increase in the reduction temperature favors the formation of CeOCl entities, thus stabilizing Ce (III) species [17,31] and, consequently, producing a decrease of the OSC [22,29,[32][33][34] . This effect could affect the catalytic activity and in fact, as will be discussed below, a poorer CO conversion in the case of the Cl-containing catalyst reduced at 773 K than reduced at 523 K was observed, probably due to decrease of the OSC.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Influence of the metal precursor on the catalytic behavior of Pt/Ceria catalysts in the preferential oxidation of CO in the presence of H2 (PROX)

Jardim

Rico-Francés

Coloma

et al. 2015

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

The effect of the metal precursor (presence or absence of chlorine) on the preferential oxidation of CO in the presence of H2 over Pt/CeO2 catalysts has been studied. The catalysts were prepared using (Pt(NH3)4)(NO3)2 and H2PtCl6, as precursors, in order to ascertain the effect of the chlorine species on the chemical properties of the support and on the catalytic behavior of these systems in the PROX reaction. The results show that chloride species exert an important effect on the redox properties of the oxide support due to surface chlorination. Consequently, the chlorinated catalyst exhibits a poorer catalytic activity at low temperatures compared with the chlorine-free catalyst, and this is accompanied by a higher selectivity to CO2 even at high reaction temperatures. It is proposed that the CO oxidation mechanism follows different pathways on each catalyst. This is a previous version of the article published in Journal of Colloid and Interface Science. 2015, 443: 45-55. doi:10.1016/j.jcis.2014 3: Graphical Abstract (for review)• The presence or absence of Cl in the Pt precursor strongly affects the catalytic behavior.• The Pt precursor affects the PROX mechanism at low reaction temperatures.• At 333 K, the mechanism in the Cl-free catalyst seems to involve the -OH groups on the support.• At higher temperatures, the reaction occurs via the same mechanism on both catalysts.. Highlights (for review) AbstractThe effect of the metal precursor (presence or absence of chlorine) on the preferential oxidation of CO in the presence of H 2 over Pt/CeO 2 catalysts has been studied. The catalysts are prepared using (Pt(NH 3 ) 4 )(NO 3 ) 2 and H 2 PtCl 6 , as precursors, in order to ascertain the effect of the chlorine species on the chemical properties of the support and on the catalytic behavior of these systems in the PROX reaction. The results show that chloride species exert an important effect on the redox properties of the oxide support due to surface chlorination. Consequently, the chlorinated catalyst exhibits a poorer catalytic activity at low temperatures compared with the chlorine-free catalyst, and this is accompanied by a higher selectivity to CO 2 even at high reaction temperatures. It is proposed that the CO oxidation mechanism follows different pathways on each catalyst.

show abstract

Cerium oxidation state in ceria nanoparticles studied with X-ray photoelectron spectroscopy and absorption near edge spectroscopy

Cited by 537 publications

References 33 publications

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Techniques for the Study of the Structural Properties

Influence of the metal precursor on the catalytic behavior of Pt/Ceria catalysts in the preferential oxidation of CO in the presence of H2 (PROX)

Contact Info

Product

Resources

About