Rare-Earth Zirconate Ln2Zr2O7 (Ln: La, Nd, Gd, and Dy) Powders, Xerogels, and Aerogels: Preparation, Structure, and Properties

Rare-Earth Zirconate Ln2Zr2O7 (Ln: La, Nd, Gd, and Dy) Powders, Xerogels, and Aerogels: Preparation, Structure, and Properties

Článek WoS

The physicochemical properties of rare-earth zirconates can be tuned by the rational modification of their structures and phase compositions. In the present work, La3+-, Nd3+-, Gd3+-, and Dy3+-zirconate nanostructured materials were prepared by different synthetic protocols, leading to powders, xerogels, and, for the first time, monolithic aerogels. Powders were synthesized by the co-precipitation method, while xerogels and aerogels were synthesized by the sol−gel technique, followed by ambient and supercritical drying, respectively. Their microstructures, thermogravimetric pro-files, textural properties, and Crystallographic structures are reported. The co-precipitation method led to dense powders (SBET <1 m2 g−1 ), while the sol−gel technique resulted in large surface area xerogels (SBET = 144 m2 g−1) and aerogels (SBET = 168 m2 g−1 ). In addition, the incorporation of lanthanide ions into the zirconia lattice altered the crystal structures of the powders, xerogels, and aerogels. Single-phase pyrochlores were obtained for La2Zr2O7 and Nd2Zr2O7 powders and xerogels, while defect fluorite structures formed in the case of Gd2Zr2O7 and Dy2Zr2O7. All aerogels contain a mixture of cubic and tetragonal ZrO2 phases. Thus, a direct effect is shown between the drying conditions and the resulting crystalline phases of the nanostructured rare-earth zirconates.

The physicochemical properties of rare-earth zirconates can be tuned by the rational modification of their structures and phase compositions. In the present work, La3+-, Nd3+-, Gd3+-, and Dy3+-zirconate nanostructured materials were prepared by different synthetic protocols, leading to powders, xerogels, and, for the first time, monolithic aerogels. Powders were synthesized by the co-precipitation method, while xerogels and aerogels were synthesized by the sol−gel technique, followed by ambient and supercritical drying, respectively. Their microstructures, thermogravimetric pro-files, textural properties, and Crystallographic structures are reported. The co-precipitation method led to dense powders (SBET <1 m2 g−1 ), while the sol−gel technique resulted in large surface area xerogels (SBET = 144 m2 g−1) and aerogels (SBET = 168 m2 g−1 ). In addition, the incorporation of lanthanide ions into the zirconia lattice altered the crystal structures of the powders, xerogels, and aerogels. Single-phase pyrochlores were obtained for La2Zr2O7 and Nd2Zr2O7 powders and xerogels, while defect fluorite structures formed in the case of Gd2Zr2O7 and Dy2Zr2O7. All aerogels contain a mixture of cubic and tetragonal ZrO2 phases. Thus, a direct effect is shown between the drying conditions and the resulting crystalline phases of the nanostructured rare-earth zirconates.

Rare-Earth Zirconate; Ln2Zr2O7; La; Nd; Gd; Dy; Powders; Xerogels; Aerogels

Rare-Earth Zirconate; Ln2Zr2O7; La; Nd; Gd; Dy; Powders; Xerogels; Aerogels

TORRES RODRÍGUEZ, J.; GUTIÉRREZ CANO, V.; MENELAOU, M.; KAŠTYL, J.; CIHLÁŘ, J.; TKACHENKO, S.; GONZÁLEZ, J.; KALMÁR, J.; FÁBIÁN, I.; LÁZÁR, I.; ČELKO, L.; KAISER, J.

2020

31.12.2019

American Chemical Society

Washington, DC

1520-510X

INORGANIC CHEMISTRY

1

1

Spojené státy americké

14467

14477

11

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2019-ART-10--inorg_chem-Rare-Earth Zirconate Ln2Zr2O7-tor-men-cihl-tka-cel-kai