W-type ferrites possessing low cost and high chemical stability, show high potential in electromagnetic wave (EMW) absorption field. However, due to the low dielectric loss, developing high EMW absorption performance of W-type ferrites remains desired. Here, rare earth (RE) cerium (Ce)-doped W-type barium ferrites (Ba 1-y Ce y Ni 2 Fe 15.4 O 27 , y=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) are prepared by a sol-gel approach. The influences of Ce doping are detailed analyzed. Ce ions with unpaired 4f electrons and strong spin-orbit coupling of angular momentum enhance the dielectric and magnetic properties of ferrites. Ba 0.7 Ce 0.3 Ni 2 Fe 15.4 O 27 achieves the minimum reflection loss (RL min ) value of -52 dB while Ba 0.6 Ce 0.4 Ni 2 Fe 15.4 O 27 showcases the widest effective absorption bandwidth (EAB) of 1.36 GHz associated with the RL min reaching -38 dB, significantly outperforming the undoped ferrites. This work thus demonstrates a high-efficiency utilization of Ce for enhancing the EMW absorption performance of widely employed W-type barium ferrites, efficiently advancing the application field of RE elements.
Molten salt is an indispensable medium for the electrochemical extraction of rare earth metal cerium (Ce). However, the existing molten salt system is incapable of meeting the low-cost requirement of industrial production. The selection of molten salt electrolyte is closely related to its thermodynamic properties and its influence on electrolytic extraction in terms of electrochemical reaction and kinetics. Herein, the constructed potential fluoride electrolyte systems (CeF 3 -LiF-BaF 2 , CeF 3 -LiF-NaF, CeF 3 -LiF-KF, and CeF 3 -LiF-NaF-KF melts) were systematically investigated with respect to theoretical electrochemical window, exchange current density at the molten salt/electrode interface during electrolytic reduction, and the effect of density in rare earth deposition. From a comprehensive point of view, the choice of molten salt system for electrolysis should combine the electrochemical reaction properties of rare earth metal ions in it and the physicochemical properties of the molten salt itself. The CeF 3 -LiF-BaF 2 electrolyte was considered as the most promising molten salt system due to its various outstanding parameters (diffusion coefficients: 6.74×10 −7 cm 2 s −1 , exchange current density: 0.649 A cm −2 , density: 4.046 g·cm −3 ). This work provides new insights into fluoride electrolyte design screening.
Peng Guan,Bin Yang,Jianyong Liu,Hang Yin,Jutao Jiang,Laizhi Sui,Songqiu Yang
It is very necessary to develop stable and cheap photocatalysts without precious metals, but they can significantly increase the photocatalytic activity. Herein, we designed and fabricated novel rare-earth cerium doped C 3 N 4 (Ce-C 3 N 4 ) for boosting photocatalytic H 2 evolution. The chemical structure, morphology, photoelectrochemical and optical properties of the as-prepared Ce-C 3 N 4 was tested through a range of characterization. The as-prepared 0.01Ce-C 3 N 4 exhibited superior photocatalytic hydrogen evolution activity (≈2.6 fold) than pristine C 3 N 4 . Its excellent photocatalytic activity result from efficient charge separation and an extended carrier lifetime. This work highlights the importance of rare earth element doping for devising of highly efficient and stable photocatalysts.
The multicomponent rare-earth cerate (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 Ce 2 O 7 (5RE 2 Ce 2 O 7 ) ceramics were successfully fabricated through solvothermal method and the following calcination process. The microstructure and phase composition of the as-obtained products were systematically characterized via SEM, TEM and XRD techniques. The results showed that the as-synthesised 5RE 2 Ce 2 O 7 has a single-phase fluorite-type crystal structure with the particle size of approximately 200 nm. Furthermore, the as-synthesised 5RE 2 Ce 2 O 7 demonstrated lower thermal conductivity (1.9–1.26 W m −1 ·K −1 at 25–1000 °C), higher thermal expansion coefficients (CTEs, 12.48 × 10 −6 K −1 at 1000 °C), and outstanding mechanical properties including large Young's modulus (248.0 ± 0.35 GPa) and high fracture toughness (2.4 ± 0.21 MPam 1/2 ). The excellent properties of the as-synthesised 5RE 2 Ce 2 O 7 demonstrates its potential application as a new type of next-generation TBCs .
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