Thermal Stability of Flame‐Made Zirconia‐Based Mixed Oxides

Jossen, Rainer; Heine, M.; Pratsinis, Sotiris E.; Akhtar, M. Kamal

doi:10.1002/cvde.200506380

Cited by 24 publications

(9 citation statements)

References 28 publications

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“…The grain sizes of 4YSZ and 8YSZ calculated by the Scherrer equation were found to be about 21 nm, irrespective of the amount of yttria doping. This result is consistent with results reported by Jossen et al 44 The average particle sizes of 4YSZ and 8YSZ examined using TEM was about 27 nm with a size range from 10 to 50 nm, as shown in Fig. 8, based on the measurement of a rather limited number of particles.…”

Section: Resultssupporting

confidence: 93%

Synthesis of Yttria‐Stabilized Zirconia Nanopowders by a Thermal Plasma Process

Ryu

Choi

Hwang

et al. 2010

Journal of the American Ceramic Society

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A thermal plasma process was used to synthesize nanosized zirconia and yttria‐stabilized zirconia powders. This paper presents a new method on the synthesis of nanosized zirconia and yttria‐stabilized zirconia powders from the carbonates (zirconium carbonate and/or yttrium carbonate). The products from this process using zirconium carbonate were mixtures of monoclinic and tetragonal phases of zirconia. The amount of the tetragonal phase in the mixture increased as the plasma torch power or plasma gas flow rate increased. This is attributed to the formation of metastable tetragonal phase by rapid quenching. With the addition of yttria precursor, two combinations of zirconia phases were formed depending on the yttria contents. Pure tetragonal phase was obtained at 3.8 mol% yttria, while a mixture of tetragonal and cubic phases was produced at 7.7 mol% yttria. The yttria‐doped tetragonal phase was stable at high temperatures without the tetragonal–monoclinic phase transition. The grain size of each phase, the particle size, and the BET are also discussed in this paper.

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Section: Resultssupporting

confidence: 93%

Synthesis of Yttria‐Stabilized Zirconia Nanopowders by a Thermal Plasma Process

Ryu

Choi

Hwang

et al. 2010

Journal of the American Ceramic Society

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“…Figure shows PXRD patterns of CuO/ZrO 2 prepared at P (the precursor feed rate) = 1–10 mL min −1 and pure‐ZrO 2 prepared at P = 2 mL min −1 (FSP‐ZrO 2 ) with NiO powder as an internal standard. Regardless of the Cu loading and the precursor feed rate, the dominant phase of ZrO 2 is tetragonal (t‐ZrO 2 ), which is consistent with other FSP‐made ZrO 2 . In our FSP‐made ZrO 2 , monoclinic ZrO 2 was not formed unlike in the other case .…”

Section: Resultssupporting

confidence: 86%

“…The crystallite size of t‐ZrO 2 decreased from 6.9 to 2.6 nm by decreasing P from 10 to 1 mL min −1 . It was reported that the crystallite size of FSP‐made particles is normally comparable with their primary particle size as they are formed in a high temperature flame (e.g., ZrO 2 , TiO 2 ). Next, the content of t‐ZrO 2 was evaluated from the peak intensity of the above PXRD patterns.…”

Section: Resultsmentioning

confidence: 99%

Influences of particle size and crystallinity of highly loaded CuO/ZrO₂ on CO₂ hydrogenation to methanol

et al. 2019

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In this study, highly loaded CuO (65.2 wt%) on ZrO2 support was prepared by flame spray pyrolysis, and the effects of their particle sizes and ZrO2 crystallinity on CO2 hydrogenation to methanol were investigated. By varying the precursor feed rate (1–10 mL min−1), the crystallite size (3–7 nm) and the crystallinity of tetragonal ZrO2 were controlled. After H2 reduction at 300°C, the Cu species in the catalysts, prepared at the feed rate = 2–10 mL min−1, were converted to Cu particles (approximately 10–20 nm); however, the size and crystallinity of ZrO2 remained the same. The activity and selectivity of the catalysts prepared at the feed rate = 2–3 mL min−1 were higher than those of the catalysts prepared at the feed rates = 5–10 mL min−1, because the smaller ZrO2 particles in the former provided more surface to stabilize small Cu particles and from interfacial Cu‐ZrO2 sites (active sites).

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“…Previous studies were focused on zirconia stabilization by different kinds of additives, such cations with lower valence than Zr 4+ as Al 3+ , Y 3+ , Ca 2+ , even oxides such as CeO 2 , SiO 2 , TiO 2 whose cations have the same valence with that of the hostage have been introduced into the lattice of ZrO 2 to form heat standing materials [13][14][15][16][17][18]. Among these additives, yttria (Y 2 O 3 ) was an effective stabilizer and was most widely used.…”

Section: Introductionmentioning

confidence: 99%