Lanthanum cerate (La2Ce2O7): hydrothermal synthesis, characterization and optical properties

Abstract

La 2 Ce 2 O 7 nano-powders were synthesized via a hydrothermal reaction in a deionized water (S 1) and in a 2 M NaOH aqueous solution (S 2) at 180°C for 48 h. La(NO 3) 3 ÁH 2 O and (NH 4) 2 Ce(NO 3) 6 were used in the stoichiometric 1:1 La:Ce molar ratio as raw materials. The obtained materials were crystallized in a cubic crystal structure with space group. The synthesized materials were characterized by powder X-ray diffraction technique and Fourier-transform infrared spectroscopy. To investigate the effect of the basic solution on the morphology of the obtained materials, the morphologies of the synthesized materials were studied by field emission scanning electron microscopy technique. The technique showed that the morphology of La 2 Ce 2 O 7 samples changed from grain to rod-like structure in presence of the basic solution. Cell parameter refinements showed that these parameters were larger for S 2 than those for S 1. Photoluminescence and ultraviolet visible spectra of the synthesized nanomaterials were also investigated.

Structural, electrical and magnetic properties of substituted pyrochlore oxide nanoparticles synthesized by the co-precipitation method

“…The lattice parameter 'a' is determined from the XRD pattern using the relation a = d √h 2 + k 2 +l 2 , where d is the inter plane spacing of the diffraction peak and hkl denotes the Miller indices of the corresponding peak. The lattice parameter is given in Table 3, which is slightly less than the reported value [12,[52][53][54][55][56][57][58]. This can be due to the incorporation of dopants in to host lattice and also the nanocrystalline nature of all substituted pyrochlores.…”

EFFECTS OF Nd2O3 ON THE CRYSTALLIZATION AND PROPERTIES OF GLASS CERAMIC IN Li2O–K2O–Al2O3–SiO2–P2O5 SYSTEM

“…Crystallite sizes (nm) of LS 2 phase can be calculated via Scherrer's equation, using the maximum peak at hkl [111] (2θ ≈ 24.8°): (2) where K is the Scherrer constant and is 0.9 [16]; λ is the X-ray diffraction wavelength and is 0.154 nm; FWHM is the full width at half its maximum intensity (an angular width, in terms of 2θ); θ is the Bragg angle (in radians).…”

Effect of Sintering Temperature on Phase Evolution, Microstructure, and Mechanical Properties of La2ce2o7/40 Wt.% Ysz Composite Ceramics

“…Moreover, LC exhibits a higher CTE, lower heat transfer, and better calcium-magnesiumaluminum-silicate (CMAS) corrosion resistance than YSZ [14,16e18]. Different methods, such as solid-state synthesis [13,19], co-precipitation route [20,21], hydrothermal method [22,23], sol-gel [12,24], or molten salt method [25] can be employed for the synthesis of LC particles with various morphologies and crystallite sizes. The conventional solid-state synthesis is an easy and effective method to prepare nanosized LC with good powder homogeneity that is necessary for fabricating high-performance TBCs.…”