Samarium Metal Research Articles

Electrodeposition behaviour of samarium in 1,3-dimethyl-2-imidazolidone solvent

Abstract The present study investigates the electrochemistry spectroscopy of Sm(III), and electrodeposition of samarium metal in neutral ligand-based ionic liquid (solvate ionic liquid). Mixture consisted of a samarium precursor (either samarium triflate or samarium nitrate hexahydrate) in the solvate ionic liquid, 1.3-dimethyl-2-imidazolidone (DMI). FT-IR analysis of Sm(III)-DMI electrolytes indicates that Sm3+ ion coordinates with DMI through carbonyl group (C=O); the band splits into two with emergence of new peak at 1630 cm−1 and 1649 cm−1 for the triflate and nitrate solutions, respectively. Raman spectroscopy also confirms the solvation of Sm(III) with DMI through oxygen atom of the carbonyl group. Voltametric behaviour of Sm(III) ion indicates two-step reduction mechanism via Sm(III)/Sm(II) at ca. −2.0 V and Sm(II)/Sm(0) at ca. −3.0 V vs. Ag/Ag+ for both samarium(III)-containing electrolytes. Diffusion coefficient value of Sm(III) was determined to be 2.185 × 10−6 cm2/s and 2.418 × 10−8 cm2/s for triflate and nitrate electrolytes, respectively. Electrodeposition of samarium was achieved through constant potential electrolysis using copper substrate as the working electrode which yielded compact deposits from triflate-DMI and non-uniform granular deposit from nitrate-DMI electrolyte. Ex situ X-ray photoelectron spectroscopy analysis of the as-deposited samples revealed the presence of metallic Sm (1081 eV) co-existing with its oxide form (1083 eV).

Electrocatalytic sensing of propyl gallate in real-time food samples using a synergistic Sm-MOF@GCN composite modified glassy carbon electrode

A novel electrochemical sensor has been developed using the sonochemically synthesized samarium metal–organic framework (Sm-MOF) and the graphitic carbon nitride (GCN) composite for the selective determination of propyl gallate (PG). The as-synthesized Sm-MOF@GCN composite was characterized by XRD, XPS, and FESEM. The morphological studies of the prepared Sm-MOF@GCN composite revealed the bar-shaped Sm-MOF and porous sheet-like morphology of GCN. The combined effect of the Sm-MOF and GCN enhance the current density response and lowers the oxidation potential, which was beneficial for the electrochemical sensing of PG. Moreover, the high electrochemical active surface area (EASA) (0.0649 cm2) and the rate constant value (Ko) of 1.44x10-5 cm s−1 confirm the faster electron transfer kinetics at the interface of Sm-MOF@GCN composite. However, the developed Sm-MOF@GCN composite possesses linear range from 0.02 to 60 µM with a nanomolar detection level (2.05 nM), high sensitivity (0.1914 μA μM−1 cm−2), excellent reproducibility, repeatability, and stability for up to 30 days towards the PG detection. Finally, the Sm-MOF@GCN composite-modified electrocatalyst was utilized for the quantification of PG in foodstuffs such as instant noodles, cookies, cakes, and oils. The result of the study, the Sm-MOF@GCN composite displayed good recovery results, making it a promising candidate for detecting PG in real-world samples in view of its binder-free approach and facile fabrication process.

A highly conductive and mesoporous samarium metal–organic nanorods for the trace-level electrochemical detection of toxic mercury ions in lake water

The research outlines an ultrasensitive electrochemical detection of trace-level mercury using an Sm-BTC metal–organic framework. The Sm-BTC metal–organic framework was synthesized via a simple solvothermal method and characterized through various analytical techniques. The FTIR spectrum shows two important peaks at 732 cm−1 and 554 cm−1 which confirms the formation of the metal–organic framework and the surface morphology of the material was characterized through SEM analysis which shows the multilayered nanorod structure. The mesoporous nature of the material was confirmed by BET analysis. The electrochemical studies including Cyclic voltammetry and Square wave voltammetry prove the Sm-BTC modified glassy carbon electrode has shown remarkable sensitivity and selectivity towards the sensing of mercury ions than the unmodified bare glassy carbon electrode. The Sm-BTC modified GCE with the optimized electrochemical parameters for the sensing of mercury ions confirms that the sensor has a very low LOD (Limit of Detection) of 10 nM. It is lower than the guideline concentration of mercury (30 nM) by the World Health Organization and the linear range is 0.01 µM to 50 µM with a correlation coefficient of 0.9926. Further, this sensor has shown an excellent sensitivity of 91.760 µA µM−1 cm−2. The real sample analysis of the current study proves the reported sensor is effective for the determination of Hg2+ ions as it shows a very good recovery percentage.

Raman spectroscopy and quantum chemical calculation on SmCl3-KCl-LiCl molten salt system

The study on the ionic structure of SmCl3-KCl-LiCl molten systems is of guiding significance for the practical production of metal samarium and samarium alloys via Molten salt electrolysis (MSE) using this system as electrolyte. Based on density functional theory (DFT), the possible ionic groups in SmCl3-KCl-LiCl molten system were simulated by Gaussian and GaussView program and their theoretical Raman spectra were calculated. The calculated spectra were then compared with the experimental Raman spectra of molten 0.1–2 mol% SmCl3-(41 mol% KCl-59 mol% LiCl) to identify the ionic groups which might have existed. It is thought that SmCl4-, SmCl63-, Sm2Cl82- and Sm2Cl7- exist in the molten system. When the temperature is unchanged, the “lifetime” of SmCl63- is reduced while those of SmCl4-, Sm2Cl82- and Sm2Cl7- is increased with the increase of SmCl3 content. Within the temperature range of 773–809 K, when the content of SmCl3 remains unchanged, the “lifetime” of these complex ions decreases with the increase of temperature. Besides, the relative content of SmCl63- decreases with the increase of temperature. The wave function analysis of the four kinds of Sm-Cl ionic groups was also carried out using Multiwfn program. The net atomic charge of each ionic group, the direction of electron migration during the formation of the ionic groups, as well as the most prone to electrophilic and nuclear reactions of each ionic group, and the order of bond breaking during chemical reactions for the four groups were obtained.

A new strategy for coupling amides or nitriles with diarylketones promoted by samarium metal under the catalysis of CuI

Promoted by samarium metal, the novel condensation reaction of low activity α-H and benzophones was realized under the catalysis of cuprous iodide under the mild conditions. The carbonyls of diarylketones could be coupled with a variety of nitriles or amides, which could be converted to condensation products with good yields at room temperature, while the deoxygenation products could be obtained smoothly at 80 °C. Only 5 mol % CuI was sufficient to catalyze the reaction and the use of iodine as additive could increase the reaction efficiency obviously.

Rare Earth Metal Samarium Doped Ferrite and Its Structural, Morphological, Magnetic, and Optical Studies for Biomedical Applications

The x-ray diffraction analysis manifested the single phases of Fe2O3, SmFeO3, and v SmFeO3 synthesized via sol-gel route. The Fe2O3, SmFeO3, and v SmFeO3 were hexagonal, orthorhombic, and cubic, respectively. The Debye-Scherer formula was used to calculate the average crystallite size of Fe2O3 (85.54 nm), SmFeO3 (67.65 nm), and v SmFeO3 (49.58 nm). The FESEM reveals near-spherical morphology with average particle sizes of 173, 114, and 161 nm, respectively. VSM analysis revealed the enhanced magnetic behavior of SmFeO3 and v SmFeO3 compared to Fe2O3. Antimicrobial activity against both E. coli and S. aureus bacteria justifies the biomedical application.

Samarium(III) Triflate in Organic Synthesis: a Mild and Efficient Catalyst

AbstractLanthanides have shown great potential in the field of magnetic materials, telecommunications, hard‐disk drives, catalysis, medicine, agriculture, and more. Recently, lanthanide complexes have gained significant attention in cancer diagnosis and therapy because of the multifunctional chemical and magnetic activities of the lanthanide‐ion 4 f electronic configuration. Among lanthanides, samarium metal and its derivatives have been the subject of many applications in organic transformations. Various metal triflates such as Bi(OTf)3, Yb(OTf)3, In(OTf)3, Sc(OTf)3, Er(OTf)3, Ce(OTf)3, Sm(OTf)3, and others play a profound role in developing novel eco‐friendly protocols in organic synthesis with excellent efficiency and selectivity. Among lanthanide triflate, samarium(III) triflate has a remarkable contribution in synthesizing promising organic molecules as it has been shown to be moisture tolerant and a reusable Lewis catalyst under mild conditions. The present review aims to focus on different useful protocols using samarium(III) triflate as an efficient catalyst for the first time elegantly.

Investigation of the effect of sintering temperatures on the structural and magnetic properties of (Bi0.90Sm0.10Fe0.93Cr 0.07O3) ferrite

Rare earth samarium (Sm) and transition metal chromium (Cr) doped bismuth ferrites (Bi0.90Sm0.10Fe0.93Cr 0.07O3) are successfully fabricated using a solid state reaction method at various sintering temperatures (Ts). The distorted rhombohedral structure was confirmed by X-ray diffraction with R3c space group for 800 and 850 °C sintered compositions with some impurity peaks. The distorted rhombohedral phase changes slightly in the pseudo-cubic phase at 900 °C Ts with a nominal reduction in the percentage of some secondary phases. The average crystallite size of compositions is decreased from 71 to 23 nm and lattice strain is increased from 0.108 to 0.313% with increasing Ts. The value of the Gold-Schmidt tolerance factor is 0.84 which indicates the stabilized form of the ferrites. Field Emission Scanning Electron Microscopy images reveal the surface morphology of the compositions, and it is found that the grain size increases from 0.868 to 1.29 μm with increasing Ts. Increasing trends and a long range of frequency stable permeability suggest these compositions to use in high frequency devices. In magnetic hysteresis loops, the exchange bias effect in the negative axis direction is observed that is gradually increased with Ts. Saturation magnetization is increased from 1.780 to 1.975 emu/g following the increment trend of Bhor magnetic moment from 0.256 to 0.320 μB. The squareness ratio suggests the formation of a multidomain structure in the polycrystalline ferrites.

Selective extraction of Sm from LiCl-KCl molten salt into wasteforms via liquid bismuth

The electrorefining of spent nuclear fuels in a molten LiCl-KCl salt electrolyte recovers the valuable actinides but also releases radioactive fission products in the salt. To minimize the nuclear waste volume, dissolved fission products such as rare earths (REs) must be removed from the electrorefining salt and immobilized into proper wasteforms. Here we propose a two-step approach for treating the electrorefining waste salt by (i) the electrolytic recovery of REs from the salt using a liquid metal cathode; and subsequent (ii) oxidative extraction of REs from the liquid metal into durable wasteforms. Experimental demonstration using rare earth element samarium (Sm) and liquid metal (Bi) was successful. The Sm ions dissolved in the salt can be selectively recovered as dendrite Sm-Bi intermetallic products on the top of liquid bismuth cathode through electrolysis at appropriate applied currents or potentials. Then the Sm in the Sm-Bi alloy was efficiently extracted into both zinc-in-titania (ZIT) glass ceramic and lanthanide aluminoborosilicate (LABS) glass wasteforms through selective oxidation at Sm2O3 loadings of 18–25 wt% and 50 wt%, respectively. Recycling of the electrorefining salt with minimum nuclear waste generation is foreseeable with the use of this simple, efficient, and highly compatible process.

Samarium-Mediated Asymmetric Synthesis

Samarium is an efficient reducing agent, a radical generator in cyclization and a cascade addition reaction. Interestingly, samarium metal has crucial impact on numerous C-C and C-X (X = hetero atom) bond forming transformations. It has been established as an exceptional chemo-selective and stereoselective reagent. The reactivity of the samarium catalyst/reagent is remarkably enhanced in the presence of various additives, ligands and solvents through effective coordination and an increase in reduction potential. It has inherent character to act as electron donor for a wide range of transformations including the asymmetric version of various reactions. This review accentuates the developments in samarium-mediated/catalyzed asymmetric organic synthesis over the past 12 years, where the chirality has been induced from ligand, a nearby asymmetric center within the substrate or through coordination directed stereospecific reactions.

Rare earth metal based DES assisted the VPO synthesis for n-butane selective oxidation toward maleic anhydride

Deep eutectic solvents (DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields. Herein, vanadium phosphorus oxide (VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal (rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride (MA) is evaluated. The rE-DES is produced from the interaction of choline chloride (ChCl) and rare earth metal salts (Cerium, Europium, Lanthanum, and Samarium metal salt) (ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V4+/V5+, Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS, were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO2 as well as the CO/CO2 ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.

Young's modulus of thin SmS films measured by nanoindentation and laser acoustic wave

High quality phase pure samarium sulphide (SmS) thin films with low surface roughness were prepared by electron beam evaporation using a samarium metal source in an H2S atmosphere. SmS shows a strong piezoresistive response due to a phase transition between a semiconducting and metallic state, which can be employed in piezo-electronic devices and stress sensing. Measurement of fundamental mechanical properties such as Young's modulus is thus a major objective to assess the elastic behaviour of SmS under external stress. Nanoindentation was used to measure the elastic modulus of thin semiconducting films with nominal thickness of 100 nm, 200 nm and 400 nm on silicon substrate at different loads. The indentation results were fitted to a modified King's model to exclude the effect of the substrate, giving Young's moduli of the films in the range of 79–82 GPa, consistent with measurements with a Laser Surface Acoustic Wave system (LAwave) and results from literature.

Recovery of Samarium and Cobalt from Sm–Co Magnet Waste Using a Phosphonium Ionic Liquid Cyphos IL 104

Due to outstanding thermal stability and corrosion resistance, samarium–cobalt alloy is being used in rare earth magnet. So, this permanent magnet waste can be a potential source for rare earth metal samarium and critical metal cobalt. Recovery and reuse of Sm, Co from Sm–Co magnet waste can reduce the burden on primary resources and environmental issues related to primary resources. In this work, a hydrometallurgical method for recovery of samarium and cobalt from Sm–Co magnet waste has been developed using an ionic liquid Cyphos IL 104. The optimum separation condition for cobalt and samarium has been determined by varying the concentration of HCl, NaCl, and mixture of HCl and NaCl in the leach liquor. The McCabe–Thiele plot is constructed using 0.075 mol/L Cyphos IL 104. Three counter-current stages at A:O ratio of 1:1.5 are needed for complete extraction of cobalt into the ionic liquid phase leaving samarium in the raffinate. Precipitation stripping of cobalt from the loaded organic is carried out using oxalic acid and the cobalt oxalate, thus formed, is calcined at 450 °C to form Co3O4. The raffinate obtained from the counter-current extraction contains 2.02 g/L Sm and 0.02 mg/L Co. Sm2O3 from raffinate is produced by precipitation of samarium with oxalic acid followed by calcination of samarium oxalate at 800 °C. Both the oxide products are confirmed by XRD.

High-pressure structural systematics in samarium up to 222 GPa

Angle-dispersive x-ray powder diffraction experiments have been performed on samarium metal up to 222 GPa. Up to 50 GPa we observe the Sm type ($hR9$) $\ensuremath{\rightarrow}$ dhcp ($hP4$) $\ensuremath{\rightarrow}$ fcc ($cF4$) $\ensuremath{\rightarrow}$ distorted fcc ($hR24$) $\ensuremath{\rightarrow}\phantom{\rule{4pt}{0ex}}hP3$ transition sequence reported previously. The structure of the high-pressure phase above 93 GPa, previously reported as having a monoclinic structure with space group C2/m, is found to be orthorhombic, space group Fddd, with eight atoms per unit cell ($oF8$ in Pearson notation). This structure is the same as that found in Am, Cm, and Cf at high pressures. Analysis of samarium's equation of state reveals marked changes in compressibility in the $hP3$ and $oF8$ phases, with the compressibility of the $oF8$ phase being that of a ``regular'' metal.

Switchable Piezoresistive SmS Thin Films on Large Area

Samarium monosulfide (SmS) is a switchable material, showing a pressure-induced semiconductor to metal transition. As such, it can be used in different applications such as piezoresistive sensors and memory devices. In this work, we present how e-beam sublimation of samarium metal in a reactive atmosphere can be used for the deposition of semiconducting SmS thin films on 150 mm diameter silicon wafers. The deposition parameters influencing the composition and properties of the thin films are evaluated, such as the deposition rate of Sm metal, the substrate temperature and the H2S partial pressure. We then present the changes in the optical, structural and electrical properties of this compound after the pressure-induced switching to the metallic state. The back-switching and stability of SmS thin films are studied as a function of temperature and atmosphere via in-situ X-ray diffraction. The thermally induced back switching initiates at 250 °C, while above 500 °C, Sm2O2S is formed. Lastly, we explore the possibility to determine the valence state of the samarium ions by means of X-ray photoelectron spectroscopy.

Hydrothermal synthesis and characterization of samarium doped BiPO4 with enhanced photocatalytic activity under UV radiation

Samarium doped BiPO4 photocatalyst was synthesized by a simple hydrothermal method. The structural, morphological and optical properties were investigated using XRD, FTIR, SEM, EDS, and UV-DRS techniques. The XRD analysis confirms pure hexagonal and well crystallized structure of the synthesized photocatalyst and average crystallite size of the doped catalyst was 23.28 nm. Fourier transform infrared (FTIR) spectra show stretching and bending vibrations of PO4 group corresponding to hexagonal structure. SEM images showed that the samples have spherical like morphology and EDS confirms the presence of samarium metal. The photocatalytic activity of Sm3+-BiPO4 samples were evaluated for the degradation of methylene blue dye in aqueous solution under UV light irradiation. The color removal efficiency of Sm3+-BiPO4 and pure BiPO4 was 97% and 66% after 50 min. irradiation, respectively. The enhanced photocatalytic activity could be mainly attributed to the charge separation. Sm3+ doping improved the photocatalytic activity of BiPO4 in degrading methylene blue.

Lewis-Acid Stabilized Organoimide Complexes of Divalent Samarium, Europium, and Ytterbium.

Discrete organoimide complexes of the divalent rare-earth metals samarium, europium, and ytterbium are reported. Tandem salt metathesis-protonolysis reactions using LnII bis(tetramethylaluminate) precursors [Ln(AlMe4 )2 ]n and monopotassium salts of 2,6-diisopropylaniline (H2 NDipp) and triphenylsilylamine prove viable and efficient protocols. Depending on the ionic radius of the LnII metal centers and the steric demand of the imido carbon backbone, mono- and dilanthanide arrangements of general composition [(thf)x Ln(NR)(AlMe3 )]y (Ln=Sm, Eu, Yb; R=Dipp, SiPh3 ) are found in the solid state. Complex formation and stabilization is achieved by coordination of the Lewis acid AlMe3 , which also prevents formation of higher aggregated species. The feasibility of redox chemistry is shown with the plumbocene derivative Cp*2 Pb, providing access to the corresponding monomeric LnIII half-sandwich complexes [Cp*Ln(NR)(AlMe3 )(thf)2 ] (Ln=Sm, Yb).

Preparation and characterization of Sm2Fe17 alloy in LiF-CaF2-SmF3 molten salt

A suitable temperature range of Sm2Fe17 alloy formed only was chosen to investigate the electroreduction of Sm3+ on molybdenum and iron electrode in LiF-CaF2-SmF3 molten salt, which were studied by CV and SWV at different temperatures and concentrations of Sm3+. The reduction of Sm3+ to Sm0 on the iron electrode included two steps. Firstly, a soluble-soluble reaction appears at −0.33 V vs. Cr/Cr2O3 corresponds to the electroreduction of Sm3+ to Sm2+. The electroreduction of Sm3+ to Sm2+ is a reversible process, which is controlled by the diffusion of Sm3+ in the LiF-CaF2-SmF3 molten salt. Secondly, Sm2+ can be reduced at −0.78 V vs. Cr/Cr2O3 on the iron electrode in LiF-CaF2-SmF3 molten salt due to a lower activity of metallic samarium in the Sm2Fe17 alloy than that of samarium metal, and that makes samarium in Sm-Fe alloy more stable while that of Sm2+ could be not reduced by a molybdenum electrode. By experiment of potentiostatic electrolysis it was confirmed that the cathode product from LiF-CaF2-SmF3 melts at −1 V vs. Cr/Cr2O3 for 4 h is a thin layer metallic plate only composing Sm2Fe17 alloy.

Thermodynamic Investigation of the Reduction-Distillation Process for Rare Earth Metals Production

Owing to their high vapor pressure, the four rare earth metals samarium, europium, thulium, and ytterbium are produced by reduction-distillation whereby their oxides are reduced with metallic lanthanum in vacuo, and the produced metal is subsequently vaporized off. Here, we performed a thorough thermodynamic investigation to establish a fundamental understanding of the reduction-distillation process. Thermodynamic functions including vapor pressures, Gibbs free energies, and enthalpies of reaction were calculated and compared with available experimental data. Furthermore, the kinetics of the process was explored and theoretical evaporation rates were calculated from thermodynamic data. The thermodynamic model developed in this work can help optimize processing conditions to maximize the yield and improve the overall process.

Structural characteristics of samarium oxynitride on silicon substrate

Thermal oxynitridation of 20 nm sputtered pure samarium metal film on silicon substrates were carried out in nitrous oxide gas ambient at various temperatures (600–900 °C) for 15 min. Influences of the oxynitridation temperature on the structural and chemical properties of the SmxOyNz films had been investigated. The crystallinity of the SmxOyNz film and existence of the interfacial layer (SmaSibOcNd) had been evaluated by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman analysis. Crystallite size and microstrain of Sm2O3 were estimated by the Williamson-Hall (W-H) plot analysis. The calculated crystallite size of the Sm2O3 from Scherrer equation were compared with the calculated values from the W-H plot. The SmxOyNz film composed of SmO and SmN phases and its interfacial layer composed of mixed SmO, SmN, SmSiO, and SiN phases were observed by X-ray photoelectron spectrometer (XPS). The amount of SmO and SmN bonds at/near to the surface was higher than those at interfacial layer. High resolution transmission electron microscopy (HRTEM) attached with the energy dispersive X-ray (EDX) spectroscopy analysis was carried out to investigate the cross sectional morphology and the chemical distribution of selected regions. A physical model related to the polycrystalline structure of the SmxOyNz film and the amorphous structure of interfacial layer had been suggested and explained. Supportive results related to model were obtained by the FTIR, XRD, Raman, EDX, and HRTEM analysis. For 800 °C and 900 °C samples, the significant changes in the thickness of interfacial layer may also due to huge amount of NO produced during decomposition of N2O gas at 1000 K and above. No silicon dioxide or samarium silicide were formed between samarium oxynitride and Si substrate.