The First Structure of a Cerium(<scp>IV</scp>) Phosphate: Ab Initio Rietveld Analysis of CeIV(PO4)(HPO4)0.5(H2O)0.5

Nazaraly, Micaela; Wallez, Gilles; Chanéac, Corinne; Tronc, E.; Ribot, François; Quarton, M.; Jolivet, Jean‐Pierre

doi:10.1002/ange.200501871

Cited by 6 publications

(5 citation statements)

References 27 publications

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“…This is in line with what reported by Nazaraly et al, 56 who used TGA for following the reduction of Ce(IV) to Ce(III). Indeed, aer calcination at 1173 K, the samples appear a white-grey powder while they are yellow when not calcined and grey when calcined at 872 K. The thermal treatment at 1173 K may produce a mixture of Ce(III)-Ce(IV) compounds, as demonstrated by XPS analysis that shows a composition 75% of CePO 4 and 25% of Ce(P 3 O 9 ).…”

Section: Resultssupporting

confidence: 92%

“…Indeed, aer calcination at 1173 K, the samples appear a white-grey powder while they are yellow when not calcined and grey when calcined at 872 K. The thermal treatment at 1173 K may produce a mixture of Ce(III)-Ce(IV) compounds, as demonstrated by XPS analysis that shows a composition 75% of CePO 4 and 25% of Ce(P 3 O 9 ). This is in line with what reported by Nazaraly et al, 56 who used TGA for following the reduction of Ce(IV) to Ce(III). These gures suggest that upon the use in catalysis there is a modication of the structure and the composition of the Cephosphate.…”

Section: Resultssupporting

confidence: 92%

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Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

et al. 2015

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In this paper, we present the results of a study on 5-HMF production from fructose by means of heterogeneous catalysts in aqueous media. Mild conditions were used, setting the temperature between 393 K and 443 K. Cerium(IV) phosphates, different from other metal(IV)-phosphates, such as titanium and zirconium, have been characterized only recently. Ce-phosphates are quite complex structures as they show several arrangements. They undergo leaching of the phosphate group as phosphoric acid with consequent slow de-activation of the catalysts. The leaching rate depends on the nature and on the temperature of the calcination of the original phosphates. This opened the question whether the conversion was driven by the heterogeneous catalysts or by the soluble phosphoric acid. A specific test has demonstrated that the solid catalysts are responsible for the conversion of fructose into 5-HMF, more than the liquid phase. We have also demonstrated that the leached phosphate is substituted by fructose on the solid catalyst. A best yield of 52% with selectivity of 93% in batch and 24% in a flow reactor at 443 K (single pass) with a selectivity also >95% were obtained.

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 92%

Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

et al. 2015

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“…Nevertheless, the green color is specific for Ce(III) monazite, CePO 4 . The SEM analyses indicates that Ce(IV) reduced to Ce(III) as CePO 4 (this process being signalized previously for other Ce(IV) phosphates [10][11][12]) while Ba accumulates in a secondary amorphous phase.…”

Section: Bace(po 4 )supporting

confidence: 64%

Synthesis and Characterisation of BaMIV(PO4)2 in the View of Conditioning of the Actinides

Popa¹,

Konings

Bouëxière

et al. 2006

Advances in Science and Technology

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We present here a systematic study on the BaMIV(PO4)2 double phosphates. We successfully synthesized the compounds with MIV = Ti, Zr, Hf, Ge, Sn and Th. Several attempts to obtain the compounds with MIV = Pb, Re, Ce, U and Np have been also performed and the preliminary findings are discussed here. In agreement with previous studies, the BaMIV(PO4)2 (MIV = Ti, Zr, Hf, Ge and Sn) compounds crystallize in the C1 2/m 1 space group (yavapaiite structure), while BaTh(PO4)2 exhibit a different structure. The results on the stability of the BaZr(PO4)2 and BaHf(PO4)2 yavapaiite-like compounds upon heating and cooling are presented.

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“…Unfortunately, there is no reliable way to estimate the relative amounts of phosphate and Ce (and hydration water) in the film, but their combined mass exceeds that of GO. In the (PP/Ce) multilayers, the XPS spectra indicated a Ce/P atomic ratio of 4.5:1, much higher than in cerium phosphates, 61 suggesting the incorporation of free Ce(IV) aqua ions in the film. 38 This was supported by the Ce 3d spectra, which showed the presence of CeO 2 in the dried film.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Oxidative Layer-By-Layer Multilayers Based on Metal Coordination: Influence of Intervening Graphene Oxide Layers

et al. 2018

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Layer-by-layer (LbL) fabricated oxidative multilayers consisting of successive layers of inorganic polyphosphate (PP) and Ce(IV) can electrolessly form thin conducting polymer films on their surface. We describe the effect of substituting every second PP layer in the (PP/Ce) multilayers for graphene oxide (GO) as a means of modifying the structure and mechanical properties of these (GO/Ce/PP/Ce) films and enhancing their growth. Both types of LbL films are based on reversible coordinative bonding between the metal ions and the oxygen-bearing groups in PP and GO, instead of purely electrostatic interactions. The GO incorporation leads to the doubling of the areal mass density and to a dry film thickness close to 300 nm after 4 (GO/Ce/PP/Ce) tetralayers. The film roughness increases significantly with thickness. The (PP/Ce) films are soft materials with approximately equal shear storage and loss moduli, but the incorporation of GO doubles the storage modulus. PP displays a marked terminating layer effect and practically eliminates mechanical losses, making the (GO/Ce/PP/Ce) films almost pure soft elastomers. The smoothness of the (PP/Ce) films and the PP-termination effects are attributed to the reversible coordinative bonding. The (GO/Ce/PP/Ce) films oxidize pyrrole and 3,4-ethylenedioxythiophene (EDOT) and form polypyrrole and PEDOT films on their surfaces. These polymer films are considerably thicker than those formed using the (PP/Ce) multilayers with the same nominal amount of cerium layers. The GO sheets interfere with the polymerization reaction and make its kinetics biphasic. The (GO/Ce) multilayers without PP are brittle and thin.

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The First Structure of a Cerium(IV) Phosphate: Ab Initio Rietveld Analysis of Ce^IV(PO₄)(HPO₄)_0.5(H₂O)_0.5

Cited by 6 publications

References 27 publications

Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

Synthesis and Characterisation of BaM<sup>IV</sup>(PO<sub>4</sub>)<sub>2</sub> in the View of Conditioning of the Actinides

Oxidative Layer-By-Layer Multilayers Based on Metal Coordination: Influence of Intervening Graphene Oxide Layers

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The First Structure of a Cerium(IV) Phosphate: Ab Initio Rietveld Analysis of CeIV(PO4)(HPO4)0.5(H2O)0.5

Cited by 6 publications

References 27 publications

Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions

Synthesis and Characterisation of BaM<sup>IV</sup>(PO<sub>4</sub>)<sub>2</sub> in the View of Conditioning of the Actinides

Oxidative Layer-By-Layer Multilayers Based on Metal Coordination: Influence of Intervening Graphene Oxide Layers

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The First Structure of a Cerium(IV) Phosphate: Ab Initio Rietveld Analysis of Ce^IV(PO₄)(HPO₄)_0.5(H₂O)_0.5