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Kijkowska, Regina; Cholewka, E.; Duszak, B.

doi:10.1023/a:1021188810349

Cited by 99 publications

(54 citation statements)

References 12 publications

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“…46-1439, LaPO 4 · 0.5H 2 O) is shown in Figure 10. Unlike for bulk hexagonal LaPO 4 [23] the intensity of the (200) peak for our samples is higher than the (102) peak, which corresponds to the (100) intensity peak for the pure …”

Section: Mechanism Of Nanorod Formationcontrasting

confidence: 62%

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

Komban¹,

Palantavida²,

Seidel³

et al. 2007

Adv Funct Materials

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Synthesis of rod‐shaped nanocrystalline lanthanum phosphate with an average length of 40 nm even after calcination at 400 °C has been realized through a room‐temperature aqueous sol–gel process. The sol is characterized by particle‐size, zeta‐potential, and viscosity measurements. Gelation of the sol is induced by ammonia. The lanthanum phosphate phase‐formation process is followed by thermal, Fourier‐transform IR, and X‐ray diffraction analysis. Transmission electron microscopy shows that the sol and gel particles have a rod‐shaped morphology and comparable particle sizes. Using the Scherrer equation a crystallite size of 11 nm is obtained for the gel powder calcined at 400 °C and Brunauer–Emmett–Teller (BET) nitrogen‐adsorption analysis showed a high specific surface area of 100 m2 g–1. Ammonia temperature‐programmed desorption measurements show that the density of Lewis acid sites is four times higher than ever reported in the case of lanthanum phosphates. The catalytic activity of the above sample is demonstrated by using it as a Lewis‐acid catalyst in an acetal‐formation reaction with a very good yield of 85 %. The sol is used to develop nanocoatings on a glass surface and the morphology of the coatings is investigated using atomic force microscopy and scanning electron microscopy. The microstructure of the coating confirmed the rod‐shaped nature of the sol particles. The coating was uniform with a thickness of about 55 nm.

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Section: Mechanism Of Nanorod Formationcontrasting

confidence: 62%

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

Komban¹,

Palantavida²,

Seidel³

et al. 2007

Adv Funct Materials

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“…The maintenance of the tetragonal modification was also confirmed in our laboratory, however, the ignition caused contraction of the unit cell of ErPO 4 .H 2 O and other tetragonal lanthanide phosphates [12,13]. It was believed the contraction was linked with the loss of water molecules.…”

Section: Resultssupporting

confidence: 56%

Ca for Er substitution in tetragonal ErPO₄ · H₂O crystallised from phosphoric acid solution

Kijkowska¹

2004

Cryst. Res. Technol.

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Erbium phosphate monohydrate with limited Ca for Er substitution, obtained through crystallisation from boiling phosphoric acid solution has been characterised by X-ray diffraction, Ir-spectroscopy and thermal analysis (TGA-DTA) methods. The difference in the electric charge between di-valent calcium and tri-valent erbium in the solid crystallised was compensated by simultaneous substitution of HPO 4 2-for PO 4 3-. Ca incorporation in erbium phosphate made expansion of tetragonal ErPO 4 .H 2 O unit cell. After ignition at 900 o C the tetragonal crystal modification was maintained but the unit cell parameters of all the investigated phosphates, whether Ca-substituted or Ca-free, contracted to the same level. The unique contraction of the unit cell was resulted from recrystallisation of Ca-substituted into Ca-free erbium phosphate, while Ca was transferred into Ca(PO 3 ) 2 formed as a separate phase.

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“…3 and 4) also show the achievement of tetragonal solids and display the sets of bands typical of tetrahedral groups (orthophosphate and orthovanadate) distorted to a D 2d symmetry, in accordance with the I4 1 /amd structure. 25,26 In the pure phosphate IR spectrum (Fig. 3), the broad band with two components centred at ∼1050 cm −1 is ascribed to the P-O anti-symmetric stretching (ν 3 , B 2 + E), whereas the doublet with bands at 648 and 524 cm −1 is related to the anti-symmetric deformation (ν 4 , B 2 + E) in PO 4 3− groups.…”

Section: Methodsmentioning

confidence: 99%

Effect of the vanadium(v) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

2012

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Nanosized rare earth phosphovanadate phosphors (Y(P,V)O 4 :Eu 3+ ) have been prepared by applying the organic-inorganic polymeric precursors methodology. Luminescent powders with tetragonal structure and different vanadate concentrations (0%, 1%, 5%, 10%, 20%, 50%, and 100%, with regard to the phosphate content) were then obtained for evaluation of their structural and spectroscopic properties. The solids were characterized by scanning electron microscopy, X-ray diffractometry, vibrational spectroscopy (Raman and infrared), and electronic spectroscopy (emission, excitation, luminescence lifetimes, chromaticity, quantum efficiencies, and Judd-Ofelt intensity parameters). The solids exhibited very intense 5 D 0 → 7 F J Eu 3+ transitions, and it was possible to control the luminescent characteristics, such as excitation maximum, lifetime and emission colour, through the vanadium(V) concentration. The observed luminescent properties correlated to the characteristics of the chemical environments around the Eu 3+ ions with respect to the composition of the phosphovanadates. The Eu 3+ luminescence spectroscopy results indicated that the presence of larger vanadium(V) amounts in the phosphate host lattice led to more covalent and polarizable chemical environments. So, besides allowing for control of the luminescent properties of the solids, the variation in the vanadate concentration in the obtained YPO 4 :Eu 3+ phosphors enabled the establishment of a strict correlation between the observable spectroscopic features and the chemical characteristics of the powders.

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Cited by 99 publications

References 12 publications

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

Ca for Er substitution in tetragonal ErPO₄ · H₂O crystallised from phosphoric acid solution

Effect of the vanadium(v) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

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Untitled

Cited by 99 publications

References 12 publications

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings

Ca for Er substitution in tetragonal ErPO4 · H2O crystallised from phosphoric acid solution

Effect of the vanadium(v) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

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About

Ca for Er substitution in tetragonal ErPO₄ · H₂O crystallised from phosphoric acid solution