Homogeneously Eu 3+ doped LaOCl single crystals are firstly synthesized in a molten KCl-LiCl flux, and the well-shaped LaOCl:Eu 3+ polyhedral micro-plates exhibit noticeable luminescent properties. The bulk LaOCl:Eu 3+ micro-plate with a width of 1.03 μm and 1.37 μm in length shows a single crystal characteristic with the crystal face orientation of [00 1 ‾ ]. Both XRD patterns and EDS mapping indicate that the Eu 3+ ions have been homogeneously doped into LaOCl lattice. LaOCl:Eu 3+ nucleuses generated in molten KCl-LiCl flux at even 350 °C benefited to the decomposition of La(OH) 3 :Eu 3+ precursor, and polyhedral LaOCl micro-plate is easily formed in molten KCl-LiCl salt due to the solid-ionic reaction and crystal growth. The luminescent properties of LaOCl:Eu 3+ are firstly enhanced and then weakened with the increasing concentration of the doped Eu 3+ , 6% Eu 3+ doped LaOCl:Eu 3+ exhibits the best luminescent properties which can be used as a potential LED material.
Zhiyao Chu,Junqi Li,Yuan-Pei Lan,Chaoyi Chen,Jian Yang,Deyang Ning,Xuewen Xia,Xisong Mao
A ternary photocatalyst of LaOCl/CeO 2 -g-C 3 N 4 was designed and firstly synthesized by a facile KCl–LiCl molten salt method. The 60 %LaOCl/40 %CeO 2 -g-C 3 N 4 with a 6: 4 weight ratio of LaOCl to CeO 2 has an optimal degradation ratio (nearly 100%) for methylene blue (MB) with an impressive cyclic stability. Both of adsorption and photodegradation contribute to the high MB removal ratio, and kinetic study results show that the rate constant of photocatalytic degradation route is 0.0174 min −1 , which is less than that of adsorption process (2.4406 min −1 ). The excellent adsorption performance of 60 %LaOCl/40 %CeO 2 -g-C 3 N 4 is attributed to its negative zeta potential (−35.40 mV) and larger average pore size. The photochemical characterizations suggest that the 60 %LaOCl/40 %CeO 2 -g-C 3 N 4 form a dual Z-scheme heterojunction , which enhances its separation efficiency of photogenerated e - / h + with an outstanding redox ability, and further promotes the photocatalytic activity.
In order to improve the utilization of spent fuel, electrolysis is used to recover fissile elements from nuclear waste samarium. The electrochemical behaviors of Sm(III) and Pb(II) were examined by CV, SWV, and OCP techniques in LiCl–KCl molten salts at 773 K. The redox mechanism of Sm(III) ions on the liquid Pb thin film electrode was analyzed. The results demonstrate that Sm(III) electro-reduction at the inert W electrode only occurred in a soluble–soluble electrochemical transition Sm(III)/Sm(II). Additionally, the kinetic parameters of samarium and lead ions were computed. The activation energies of diffusion for Sm(III) and Pb(II) were 32.92 kJ mol −1 and 35.21 kJ mol −1 , respectively. SmPb 3 and Sm 2 Pb intermetallic compounds were derived using constant potential electrolysis and constant current electrolysis at the Pb electrode in a molten salt system. The cathodic deposition output was characterized by XRD and SEM–EDS. The ICP-AES results showed that the average extraction ratio of Sm on the Pb electrode was about 94.23%.