Thermal decomposition of the hydrated basic carbonates of lanthanides and yttrium in CO2 atmosphere

D’Assunção, Lázaro Moscardini; Ionashiro, Massao; Rasera, D. E.; Giolito, I.

doi:10.1016/0040-6031(93)80500-a

Cited by 19 publications

(7 citation statements)

References 6 publications

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“…In contrast to the normal carbonates, the thermal decomposition behavior of the hydroxycarbonates has not been as comprehensively studied. A limited number of studies on the hydroxycarbonates by Eyring [89,90], Charles [83], and D'Assuncao [140] have demonstrated the general decomposition pathway as outlined by equations 3-5. Charles [83] gives a relatively qualitative view on the decomposition pathways of the hydroxycarbonates and the studies by Eyring [89,90] are in general agreement with this decomposition pathway.…”

Section: Thermal Behavior Of the Rare Earth Carbonatesmentioning

confidence: 99%

“…Charles [83] gives a relatively qualitative view on the decomposition pathways of the hydroxycarbonates and the studies by Eyring [89,90] are in general agreement with this decomposition pathway. D'Assuncao [140] has given one of the most comprehensive reports on the decomposition profiles of the rare earth hydroxycarbonates, but it should be noted that no mention of crystal phase for the rare earth hydroxycarbonates was given and thus it is difficult to assess to which hydroxycarbonate phase the results can be ascribed. Specific transition temperature(s) were also not reported as the high heating rates, which have also been known to shift the transition/decomposition temperature higher [89,90,133,134], most likely made this very difficult.…”

Section: Thermal Behavior Of the Rare Earth Carbonatesmentioning

confidence: 99%

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Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

et al. 2018

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A general overview of the trends in structural and thermodynamic properties that have been identified within the hydrated normal rare earth carbonates and the rare earth hydroxycarbonates is presented. Based upon available literature, we demonstrate the trends in crystallographic unit cell parameters, thermal stability, aqueous solubility, and thermochemical properties. These trends can be attributed to both the unique chemistry and strong similarity of the rare earth elements. There are also inconsistent trends that signal research needs to better understand the structure-energy relationships of the rare earth carbonates.

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Section: Thermal Behavior Of the Rare Earth Carbonatesmentioning

confidence: 99%

Section: Thermal Behavior Of the Rare Earth Carbonatesmentioning

confidence: 99%

Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

et al. 2018

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“…A control experiment using pure BaCO 3 confirmed that its decomposition temperature was higher than 900 • C, in agreement with published data. 32 According to the decomposition temperature reported elsewhere, 33,34 the second and third stages of weight loss are likely due to the two-step decomposition of (hydrated) hydroxycarbonate, Equation 6,…”

Section: Physical and Chemical Degradation Of A Bzcy Electrolyte Disc-mentioning

confidence: 99%

Discovery and Understanding of the Ambient-Condition Degradation of Doped Barium Cerate Proton-Conducting Perovskite Oxide in Solid Oxide Fuel Cells

Yan

Zeng

Shalchi

et al. 2015

J. Electrochem. Soc.

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Proton-conducting perovskite oxides such as doped barium cerate and barium zirconate are promising electrolytes for solid oxide fuel cells (SOFCs). Here we report that the typical high performance proton conductor, BaZr 0.1 Ce 0.7 Y 0.2 O 3±δ (BZCY), is prone to physical, chemical and thereby electrochemical degradations as it ages under ambient conditions. This aging effect destroys the electrolyte disk and breaks down the perovskite lattice. Electrochemical measurements indicate degraded BZCY based SOFC suffers from significant performance losses, and various advanced materials characterization results confirm that this degradation of BZCY is exclusively caused by water and CO 2 from the surrounding environment. The water molecules catalyze the degradation, initiating and promoting the carbonatation of BZCY. The subsequent reaction with CO 2 creates two major phases: BaCO 3 nano-rod single crystals and amorphous oxide mixtures. The entire process is visualized via TEM observations, based on which we propose that this occurs via the microcrucible mechanism. As this mechanism does not incur significant segregations of decomposition products, the aged BZCY powder is easily regenerated by re-calcination. We then study the effects of doping on the stability of BZCY, showing that a higher Zr content obviously improves the aging resistance.

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“…For pure Ln(OH)CO 3 phases composed by non-aliovalent lanthanides, such as Sm(III) or Gd(III), the formation of the oxide is preceded by a first step corresponding to a total dehydroxylation and a partial decarbonation processes to give a well-defined Ln 2 O 2 CO 3 crystalline phase (eq 2), that subsequently decomposes to Ln 2 O 3 at higher temperatures (eq 3). 28,42 Pure carbonates evolve into their oxides in a single (see eq 4, Table 1). In the case of Pr(OH)CO 3 decomposition, dehydroxylation (eq 5) precedes the partial oxidation of Pr(III) and the subsequent decarbonation (eq 6), which leads to the well-defined mixed valence oxide, Pr 6 O 11 (PDF 42-1121), in which only two-thirds of Pr ions reach the tetravalent state.…”

Section: Synthesis and Chemical Characterization Of Precursorsmentioning

confidence: 99%

Hexagonal Ce_1–xLn_x(OH)CO₃ as Highly Efficient Precursors of Nanocrystalline Ln(III–IV)-Substituted Ceria

Sorbello

Jobbágy

2017

Crystal Growth & Design

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Monophasic hexagonal precursors, obeying to the formula Ce1–x Ln x (OH)CO3, are introduced herein as versatile precursors for the preparation of Ln(III–IV)-substituted nanocrystalline ceria. To this aim, three hexagonal Ce1–x Ln x (OH)CO3 families increasingly substituted with Ln(III) = Sm(III), Gd(III), or Pr(III), were prepared with high (quantitative) precipitation yields. Once Ce1–x Ln x (OH)CO3 precursors are submitted to moderate thermal treatment (5 h, 723 K, air atmosphere), the oxidation of Ce(III) centers triggers a single step massive decomposition (dehydroxylation/decarbonation), developing monophasic Ce1–x Ln x O2−δ solid solutions with Ln(IV–III) substitutions up to 30%. These binary oxides exhibit large surface areas, up to 130 m2 g–1, even larger than those obtained by means of costly procedures.

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Thermal decomposition of the hydrated basic carbonates of lanthanides and yttrium in CO2 atmosphere

Cited by 19 publications

References 6 publications

Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

Discovery and Understanding of the Ambient-Condition Degradation of Doped Barium Cerate Proton-Conducting Perovskite Oxide in Solid Oxide Fuel Cells

Hexagonal Ce_1–xLn_x(OH)CO₃ as Highly Efficient Precursors of Nanocrystalline Ln(III–IV)-Substituted Ceria

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Thermal decomposition of the hydrated basic carbonates of lanthanides and yttrium in CO2 atmosphere

Cited by 19 publications

References 6 publications

Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

Trends in Structure and Thermodynamic Properties of Normal Rare Earth Carbonates and Rare Earth Hydroxycarbonates

Discovery and Understanding of the Ambient-Condition Degradation of Doped Barium Cerate Proton-Conducting Perovskite Oxide in Solid Oxide Fuel Cells

Hexagonal Ce1–xLnx(OH)CO3 as Highly Efficient Precursors of Nanocrystalline Ln(III–IV)-Substituted Ceria

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Hexagonal Ce_1–xLn_x(OH)CO₃ as Highly Efficient Precursors of Nanocrystalline Ln(III–IV)-Substituted Ceria