(7)Li and (6)Li nuclear magnetic resonance (NMR) experiments are carried out on the perovskite Li(3x)La(1/3-x)NbO(3). The results are compared to those obtained on the titanate Li(3x)La(2/3-x)TiO3 (LLTO) in order to investigate the effect, on the lithium ion dynamics, of the total substitution of Nb(5+) for Ti(4+) in the B-site of the ABO(3) perovskites. The XRD patterns analysis reveals that this substitution leads to a change in the distribution of the La(3+) ions in the structure. La(3+) ions distribution is very important, in regard to ionic conductivity, because these immobile ions can be considered as obstacles for the long-range Li+ motion. If compared to the titanates, the compounds of the niobate solid solution have a bigger unit cell volume, a smaller number of La(3+) ions, and a higher number of vacancies. These should favor the motion of the mobile ions into the structure. This is not experimentally observed. Therefore, the interactions between the mobile species and their environment greatly influence their mobility. (7)Li and (6)Li NMR relaxation time experiments reveal that the Li relaxation mechanism is not dominated by quadrupolar interaction. (7)Li NMR spectra reveal the presence of different Li+ ion sites. Some Li+ ions reside in an isotropic environment with no distortion, some others reside in weakly distorted environments. T(1), T(1)(rho), and T(2) experiments allow us to evidence two motions of Li+. As in LLTO, T(1) probes a fast motion of the Li+ ions inside the A-cage of the perovskite structure and T(1)(rho) a slow motion of these ions from A-cage to A-cage. At variance with what has been observed in LLTO, these different Li+ ions can be differentiated through the spin-lattice relaxation times, T(1) and T(1)(rho), as well as through the transverse relaxation time, T(2).
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http://dx.doi.org/10.1021/jp051370i | DOI Listing |
Adv Mater
January 2025
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Rare earth elements (REEs) are essential for many clean energy technologies. Yet, they are a limited resource currently obtained through carbon-intensive mining. Here, bio-scaffolded proteins serve as simple, effective materials for the recovery of REEs.
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Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Tsinghua University, Beijing 100084, China.
The fundamental hydrolysis behavior of tetravalent actinide cations (An) with a high charge is crucial for understanding their solution chemistry, particularly in nuclear fuel reprocessing and environmental behavior. Using Th as a reference of the An series, this work employed both the periodic model and the cluster model to calculate the first hydrolysis reaction constant (p) of the Th aqua ion and conducted a detailed evaluation of these approaches. In the periodic model, molecular dynamics (AIMD) simulations of Th in the explicit solvation environment are conducted, using metadynamics and constrained molecular dynamics to calculate p values.
View Article and Find Full Text PDFLuminescence
January 2025
College of Science, Sichuan Agricultural University, Ya'an, Sichuan, China.
In this paper, a series of BaSrCaWO:x%Mn, y%La (x = 0.1, 0.5, 0.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Rare earth elements (REEs) are widely used in various high-tech industries. Developing affinity ligands that can detect and distinguish REEs is at the forefront of analytical chemistry. It is also interesting to understand the limits of natural biomolecules for the recognition of REEs.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
College of Science, Inner Mongolia University of Technology, Hohhot 010051, China.
Relaxor ferroelectric film capacitors exhibit high power density with ultra-fast charge and discharge rates, making them highly advantageous for consumer electronics and advanced pulse power supplies. The Aurivillius-phase bismuth layered ferroelectric films can effectively achieve a high breakdown electric field due to their unique insulating layer ((BiO) layer)). However, designing and fabricating Aurivillius-phase bismuth layer relaxor ferroelectric films with optimal energy storage characteristics is challenging due to their inherently stable ferroelectric properties.
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