SUIDIES ON SOME PROPERTIES AND CATALYSIS OF RARE EARTH HETEROPOLY ACIDS

INTRODUCTIONThough potassium salts of rare earth substituted silicotungsticacids were synthesized early in 1971 by R.D.Peacock etc.,sofar the reports about the application of the corresponding acidshave not been found.We prepared fourteen rare earth substitutedsilicotungstic acids and determined their thermal stability,IRabsorption Spectra and x-ray diffraction spectra.Furthermore,thecatalytic activities of the fourteen heteropoly acids in acid cata-lytic reaction were investigated.Our experimental results demonstrated rare earth substituted silico-tungstic acids have very high catalytic activity in the reaction of

Use of rare earth elements in single-atom site catalysis:A critical review——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

Rare earth metals are strategic resources with potential applications in optics,metallurgy and catalysis.In recent years,single-atom site catalysts(SASCs) have attracted increasing attention owing to their 100%atom efficiency and unique catalytic performances.Over the past decade,rare earth elements,including rare earth metals and their oxides,have shown great potential in SASCs.However,systematic analyses of data are still handful.In this mini-review,the use of rare earth metals and their oxides in SASCs was summarized and the results are discussed.A particular focus was paid to the synthetic strategies,characterization of rare earth-containing SASCs,and applications as catalysis supports,promoters and active sites.Current issues faced by rare-earth metals and their oxides in SASCs,as well as future prospects were also provided.

Er_(2)TiO_(5)@Ag nanocomposites:Enhanced photocatalysis and bacteria inactivation,and cytotoxicity

In this study,we successfully synthesized Er_(2)TiO_(5)@Ag nanocomposites(NCPs) using the ultrasonicmediated sol-gel technique to create a multifunctional material with enhanced photocatalytic and antibacterial properties.The visible light photocatalytic activities of Er_(2)TiO_(5) nanoparticles(NPs) and Er_(2)TiO_(5)@Ag NCPs were systematically evaluated under various conditions,including different concentrations of Basic Blue 41(BB 41) dye and photocatalyst.The results reveal a remarkable improvement in the photocatalytic degradation efficiency of Er_(2)TiO_(5)@Ag NCPs(95%) compared to Er_(2)TiO_(5) NPs(80%).Furthermore,the antibacterial efficacy of Er_(2)TiO_(5) NPs and Er2TiO_5@Ag NCPs were extensively examined against Gram-positive and Gram-negative bacteria.Notably,Er_(2)TiO_(5)@Ag NCPs exhibit significantly higher minimum bactericidal concentration(MBC) values compared to Er_(2)TiO_(5) NPs.The antibacterial effect of Er_(2)TiO_(5)@Ag NCPs is particularly pronounced against S.aureus and Pseudomonas aeruginosa,while demonstrating moderate effects on Escherichia coli and Enterococcus faecalis.To assess the biocompatibility of the synthesized materials,we investigated their internalization by MCF-7 cells.Encouragingly,both Er_(2)TiO_(5) NPs and Er_(2)TiO_(5)@Ag NCPs are found to be effectively internalized by the cells,suggesting their potential application in biomedical fields.Intriguingly,our study unveils the exceptional potential of Er_(2)TiO_(5)@Ag NCPs as a dual-action solution,simultaneously possessing enhanced photocatalytic efficiency and potent antibacterial properties.This multifunctional nanocomposite not only outperforms Er_(2)TiO_(5) and Ag but also paves the way for innovative applications in sustainable environmental remediation and advanced biomedical technologies,promising a brighter and cleaner future.

Rare earth metal triflates catalyzed electrophilic nitration using N_2O_5

A mild,efficient and eco-friendly process for the electrophilic nitration is described using N_2O_5 as a green nitrating agent in the presence of rare earth metal triflates[RE（OTf）_3]under mild conditions.

Hydriding/dehydriding properties of NdMgNi alloy with catalyst CeO_2

Hydrogen storage composites Nd2Mg17-50 wt.%Ni-x wt.%CeO2（x=0, 0.5, 1.0, 1.5, 2.0） were obtained by induction-ball milling method. The catalytic effect of CeO_2 on hydriding kinetics of Nd_2Mg17-50 wt.%Ni composite was investigated. X-ray diffraction（XRD） and high resolution transmission electron microscopy（HRTEM）, selected area electron diffraction（SAED） analyses showed that Nd_2Mg17-50 wt.%Ni alloy had a multiphase structure, consisting of NdMg12, NdMg_2Ni, Mg_2Ni and Ni phases and the addition of catalyst CeO_2 prompted the composites to be partly transformed into amorphous strucutre. The CeO_2 improved the maximum hydrogen capacity of Nd_2Mg17-50 wt.%Ni alloy from 3.192 wt.% to 3.376 wt.%（x=1.0）. What＇s more, the increment of diffusion coefficient D led to the faster hydriding kinetics, which was calculated by Avrami-Erofeev equation. The dehydrogenation temperature reduced from 515.54 to 504.72 K was mainly caused by the decrease of activation energy from 93.28 to 69.36 kJ /mol, which was proved by the Kissinger equation.