Solubility of Nanocrystalline Cerium Dioxide: Experimental Data and Thermodynamic Modeling

Plakhova, Tatiana V.; Romanchuk, Anna Yu.; Yakunin, S. N.; Dumas, Thomas; Demir, Selvan; Wang, Shuao; Minasian, Stefan G.; Shuh, David K.; Tyliszczak, Tolek; Shiryaev, A. A.; Егоров, А. В.; Ivanov, V. K.; Kalmykov, Stepan N.

doi:10.1021/acs.jpcc.6b05650

Cited by 111 publications

(103 citation statements)

References 110 publications

(220 reference statements)

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“…Nano-ceria stability in water has been tuned by pH variation via induced surface charges as function of ageing time and temperature [41]. A recent ex-situ study of solution chemistry [26] proposes Ce III released from CeO 2 particles in water below pH=4. Such reductive dissolution is much faster than Ce IV release at higher pH [26], matching therefore our case of dissolution exceeding any previously reported rates.…”

Section: Discussionmentioning

confidence: 99%

“…In agreement with [28][29][30], we point to the possibility of (metastable) hydroxide complexes forming possibly still in dispersion. There are two ways out of the metastable region (bottom left of Pourbaix diagram), either by upwardshift through oxidative precipitation [26,27] leading to quaternary hydroxides, or through pH-reversal [48], leading to ternary hydroxides. Growth of solid or gel-type precipitates of Ce(OH) 4 = CeO 2 .…”

Section: S 72 S 0 S (A) (B) (C)mentioning

confidence: 99%

“…A detailed study of ex-situ irradiative ceria dissolution in water from a nuclear materials point of view [25] finds evidence of radiation-induced acceleration of dissolution. Solubility of cerium phases and dissolved ionic species have been discussed as function of pH [26,27], based on earlier work. [28][29][30] Here we use liquid cell TEM for a first comprehensive and dedicated study of the multi-stage corrosion behaviour of nanostructured CeO 2 in water under radiolytic conditions.…”

Section: Introductionmentioning

confidence: 99%

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In-situ observation of radiation physics and chemistry of nanostructured cerium oxide in water

Asghar¹,

Inkson²,

Seal³

et al. 2018

Mater. Res. Express

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Room temperature electron irradiation in aqueous environment is applied to CeO 2 nanoparticles using a transmission electron microscope equipped with liquid environmental cell. Oxide dissolution kinetics become accessible at unprecedented scale of spatial and time resolution through irradiation activation of water within a sub-µm size volume, allowing direct measurements of transformation rate and morphologies. Successful liveobservation of the formation of nano-needles provides essential inside in how 1D-nanostructures can form. Furthermore, formation of hydrogen bubbles is found and interpreted in relation to the dose needed for ceria dissolution. The results are of importance for many research applications of ceria in water, e.g. for catalysis, environmental remediation, biomedical radiation protection, anti-corrosion coatings, and ultimately via analogy to UO 2 also for fission-power fuel engineering and waste disposal.

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Section: Discussionmentioning

confidence: 99%

Section: S 72 S 0 S (A) (B) (C)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In-situ observation of radiation physics and chemistry of nanostructured cerium oxide in water

Asghar¹,

Inkson²,

Seal³

et al. 2018

Mater. Res. Express

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“…It also is not possible to determine a true solubility of CeO 2 owing to the formation of the passivating hydrated surface layer, so the solubility reported for anhydrous CeO 2 , which is 6.82 × 10 −14 g/L [48], actually is that of a mixture of a majority of solid CeO 2 ·2H 2 O and a minority of gelled Ce(OH) 4 , as shown in the speciation diagram of Figure 4. Since anhydrous phases typically have solubility product constants that are greater (by less than an order of magnitude) than the corresponding hydrated phases [49], it then can be assumed that the solubility of pure CeO 2 , if it could be determined, would be greater than that of both solid CeO 2 ·2H 2 O and gelled Ce(OH) 4 .…”

Section: Speciation Diagramsmentioning

confidence: 99%

“…The recent experimental investigation of CeO 2 solubility in water by Plakhova et al [48] revealed two relevant phenomena:…”

Section: Speciation Diagramsmentioning

confidence: 99%

Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

et al. 2017

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Abstract:The present work describes the effects of water on Fe-doped nanoparticulate CeO 2 , produced by flame spray pyrolysis, which represent a critical environmental issue because CeO 2 is not stable in typical atmospheric conditions. It is hygroscopic and absorbs~29 wt % water in the bulk when exposed to water vapor but, more importantly, it forms a hydrated and passivating surface layer when immersed in liquid water. In the latter case, CeO 2 initially undergoes direct and/or reductive dissolution, followed by the establishment of a passivating layer calculated to consist of~69 mol % solid CeO 2 ·2H 2 O and~30 mol % gelled Ce(OH) 4 . Under static flow conditions, a saturated boundary layer also forms but, under turbulent flow conditions, this is removed. While the passivating hydrated surface layer, which is coherent probably owing to the continuous Ce(OH) 4 gel, would be expected to eliminate the photoactivity, this does not occur. This apparent anomaly is explained by the calculation of (a) the thermodynamic stability diagrams for Ce and Fe; (b) the speciation diagrams for the Ce 4+ -H 2 O, Ce 3+ -H 2 O, Fe 3+ -H 2 O, and Fe 2+ -H 2 O systems; and (c) the Pourbaix diagrams for the Ce-H 2 O and Fe-H 2 O systems. Furthermore, consideration of the probable effects of the localized chemical and redox equilibria owing to the establishment of a very low pH (<0) at the liquid-solid interface also is important to the interpretation of the phenomena. These factors highlight the critical importance of the establishment of the passivating surface layer and its role in photocatalysis. A model for the mechanism of photocatalysis by the CeO 2 component of the hydrated phase CeO 2 ·2H 2 O is proposed, explaining the observation of the retention of photocatalysis following the apparent alteration of the surface of CeO 2 upon hydration. The model involves the generation of charge carriers at the outer surface of the hydrated surface layer, followed by the formation of radicals, which decompose organic species that have diffused through the boundary layer, if present.

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Production of Antibacterial Activity and Bone Cell Proliferation by Surface Engineering of Ga‐ or Mn‐Doped Ceria‐Coated Biomedical Titanium Alloy

et al. 2022

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The present work reports a detailed interpretation of the role of Ga and Mn dopants, solid solubility mechanisms, charge compensation mechanisms, intervalence charge transfer, antibacterial performance, and cell attachment and proliferation. Sol–gel undoped and doped (1, 5, and 9 mol%) CeO2 films are spin‐coated on 3D printed Ti6Al4V biomedical alloy substrates and annealed at 650 °C for 2 h in air. Material characterization includes scanning electron microscopy (SEM), 3D scanning laser confocal microscopy, glancing angle X‐ray diffraction (GAXRD), and X‐ray photoelectron spectroscopy (XPS). In vitro testing includes inhibition of bacterial growth, simulated body fluid (SBF) testing, and cell attachment and proliferation studies. The most significant outcome is that the bioactivity of ceria derives directly from the Ce3+ concentration, which itself results from solid solubility (substitutional and interstitial) and charge compensation and redox. This challenges the common assumption of the dominance of oxygen vacancies in the performance of ceria. The antibacterial activity is dependent on the type, amount, and valence of the dopant, where opposite trends are observed for gram‐positive Staphylococcus aureus and gram‐negative Escherichia coli bacteria. All of the doped samples result in enhanced cell proliferation, although this is greatest at the lowest dopant concentration. Surface hydroxyapatite formation on the samples is achieved by soaking in SBF at 2 weeks and 1 month.

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Solubility of Nanocrystalline Cerium Dioxide: Experimental Data and Thermodynamic Modeling

Cited by 111 publications

References 110 publications

In-situ observation of radiation physics and chemistry of nanostructured cerium oxide in water

In-situ observation of radiation physics and chemistry of nanostructured cerium oxide in water

Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

Production of Antibacterial Activity and Bone Cell Proliferation by Surface Engineering of Ga‐ or Mn‐Doped Ceria‐Coated Biomedical Titanium Alloy

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