Rare Earth Metals Gd Research Articles

Synthesis, structure, fluorescence and magnetic studies of two oxygen bridged polycarboxylic acid ligands and rare earth metal ion Pr, Gd, and Er complexes

In order to further enrich the research on the synthesis of complexes with polycarboxylic acid ligands and rare earth metal ion. In this study, four rare earth complexes, namely, [Gd(cpia)]n (1), [Er(cpia)]n (2), [Pr(cpna)2·2H2O]n (3) and [Gd(Hcpna)(cpna)•3H2O]n (4) have been synthesized by solvothermal method based on 5-(2-carboxyphenoxy)isophthalic acid (H3cpia) and 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna) with rare earth metal ions Pr3+, Gd3+ and Er3+. Single crystal X-ray diffraction analyses reveal that complexes 1, 2 and 3 are two-dimensional network structure, 4 is one-dimensional chain structures. The fluorescence test results show that the fluorescence intensity of complexes 1 and 2 were lower than that of the H3cpia ligand, the fluorescence intensity of complexes 3 and 4 were lower than that of the H2cpna ligand. Magnetic results indicate complex 1 has ferromagentic behavior and weak antiferromagentic behavior in the complexes 2, 3 and 4.

Identification of Mineral Zircon (ZrSiO4) Rare Earth Metal (REM) As Smart Material For Electric Tactical Motor Bike Battery

Rare earth metals are associated minerals that are magnetic used as the main component in providing power to most electronic devices. Rare earth metal (REM) as a smart material that has 14 chemical elements. These elements are grouped according to their molecular weight, namely light rare earth metals (Ce, Pr, Nd, Pm, Sm, Eu) and heavy rare earth metals (Gd, Tb, Dy, Ho, Tr, Tm, Yb, Lu) . The use of this REM includes electric cars, health identification devices, LCDs and computer hardware. From some of the benefits and contents of REM, its development is not only in the industrial world but also in the world of defense, one of which is as a battery for motorized vehicles developed by the ministry of defense (Electric Tactical Motor Bike) that uses lithium batteries as a source of electrical energy. However, the use of lithium batteries which have shortcomings in terms of charging makes them look for other alternatives so that they can be charged optimally, one of which is using REM. The strategic position of rare earth minerals in the future must be developed so that they can be used sustainably, considering that Indonesia has potential resources that can be utilized.

Rare earth Gd-doped NiFe2O4 @2D layered carbonaceous composite: Synthesis, structural evaluation and photocatalytic parameters studies

NiFe2O4 (F-1) and rare earth metal (Gd) doped NiFe2O4 (F-2) were prepared via a co-precipitation approach. Gd-NiFe2O4@rGO (F-3) was prepared via an ultrasonication route for the degradation of pendimethalin under sunlight. The structural confirmation of as-fabricated samples was done via XRD. The Tauc plot of F-1 showed a bandgap energy of 2.79 eV and F-2 exhibited a bandgap energy of 2.63 eV. The optical band gap was lowered due to the presence of rare-earth metal ions. NiFe2O4 and Gd-NiFe2O4 showed 48.88 %, and 61.11 % degradation of pendimethalin. Gd-NiFe2O4@rGO nanocomposite showed the highest degradation efficiency. It exhibited 84.44 % degradation of pendimethalin in 140 min at the rate of 0.01 min−1. The reason for the greater activity is due to the insertion of rare earth (Gd) ions and rGO sheets in the nickel ferrite. The doping with rare earth metal ions lowers the recombination of electrons and holes which was further supported by the addition of carbonaceous material. The surface area of the nickel ferrite was improved by rGO sheets and in turn more active sites were formed on the surface of the catalyst which fastens the rate of reaction.

Preparation and Mechanical Characteristics of Multicomponent Ceramic Solid Solutions of Rare Earth Metal Oxides Synthesized by the SCS Method

A study into the use of the Solution Combustion Synthesis (SCS) method with glycine and citric acid to synthesize fine powders of multicomponent solid solutions of oxides of rare earth (RE) metals (Nd, Sm, Eu, Gd, Dy, and Ho) for the preparation of ceramic materials is presented. Synthesis parameters of 4-, 5-, and 6-component entropy-stabilized rare earth oxides (REOs) with a C-type cubic structure are determined. The stability of entropy-stabilized oxides (ESOs) with a C-type structure is shown to depend not only on heavy RE metal quantity, but also on the rate of heating/cooling of the samples. The temperature of the polymorphic transformation of C-type REO structures into B-type (monoclinic) or H-type (hexagonal) structural variants can be described by the equation T (°C) = 0.0214Vcr2 − 62.737Vcr + 46390, where Vcr is the unit cell volume of an oxide with a C-type structure regardless of the number of cations in the solid solution. High-temperature thermal analysis up to 1250 °C revealed that dispersed powders, which contain impurities of basic carbonates along with hydroxocarbonates of RE metals and X-ray amorphous carbon formed during SCS reactions, also react with air moisture during storage. The influence of the ESO phase and cationic composition on the morphology, porosity and microhardness of ceramics was studied. Higher-entropy oxides form samples with higher density, microhardness and a smaller size of particle agglomerates.

Local atomic structure evolution of liquid gadolinium and yttrium during solidification: An ab initio study

Local atomic structure evolution of pure gadolinium (Gd) and yttrium (Y) during solidification was investigated by using ab initio molecular dynamics (AIMD) simulation. The calculated results indicate that the local short-range order (SRO) in liquid Gd and Y is similar to some transitional metals with an asymmetric shape of the second peak in static structure factors. Moreover, the formation of icosahedral local motifs as a function of temperature decreases the diffusivity, which explains the connection between structure evolution and dynamic properties. In examining the topological structures of both systems, we demonstrate that small atomic displacement leads to two different types of topological sixfold rings in liquid and solid states. All analyses yield a systematic study about rare earth metals Gd and Y at the atomic level.

USING MODERN INSTRUMENTAL METHODS FOR COFFEE IDENTIFICATION

The article provides an analysis of published works devoted to authentication of the place of origin of coffee beans, as well as the research of the main components that can be identification parameters when authenticating coffee. Based on the analysis of scientific literature, the authors noted the most significant works aimed at confirming the authenticity of the place of origin for coffee beans from Ethiopia, Kenya, Hawaii, Costa Rica, Jamaica, Brazil, Guatemala, Mexico and other countries. It was shown that the most widespread studies were aimed at analyzing the values of isotopic ratios of carbon ( 13 C/ 12 C), hydrogen ( 2 H/ 1 H), oxygen ( 18 O/ 16 O) and nitrogen ( 15 N/ 14 N) in compounds contained in coffee beans, which reflect the distribution of “light” and “heavy” isotopes during biological and geochemical processes within the boundaries of a particular region. The authors analyzed the works aimed at studying the qualitative and quantitative composition of trace elements and rare earth metals (Na, Mg, Al, Mn, Ga, Rb, Ba, Pb, Y, La, Ce, Pr, Sm, Nd, Eu, Dy, Gd and others), as well as the research of the values of isotopic ratios ( 87 Sr/ 86 Sr) in product samples and soils of the studied region. Based on the presented materials, it is concluded that the use of the isotope mass spectrometry method in combination with statistical processing of the results makes it possible to determine with a high degree of reliability the product belonging to a certain geographical region, as well as to authenticate the botanical origin of the beans. The advantages of comprehensive research of several indicators using various methods of mathematical statistics and modeling in determining the geographical place of coffee origin are shown.

Multi-elemental doped g-C3N4 with enhanced visible light photocatalytic Activity: Insight into naproxen Degradation, Kinetics, effect of Electrolytes, and mechanism

• Multi elemental doped g-C 3 N 4 was prepared by a solid-state method. • 92.9% degradation of naproxen was achieved under visible light irradiation. • Doping increased the Urbach energy of g-C 3 N 4 . • Mechanism for the degradation of naproxen was proposed. The complexity and heterogeneous existence of water pollutants ensures that development of possible large-scale water remediation technologies encompasses mimicking real water compositions. Naproxen (NPX) photocatalytic degradation in the presence of brilliant black and different electrolytes was tested, under visible light irradiation, with rare earth metals (Ce, Er, Gd, and Sm) doped graphic carbon nitride (CN) prepared via one pot solid state method. The materials were characterized with FESEM, TEM, XRD, PL, XPS, BET, UV–vis DRS, TGA, FTIR, and electrochemical techniques. Doping increased the Urbach energy compared to pristine graphitic carbon nitride due to observed shift in absorption towards the visible range of the electromagnetic spectrum, and there was proposed interaction of dopants and CN which decreased photoexcited electrons and holes recombination. The highest degradation efficiency of 92.9% was obtained at 1% loading of Ce, Er, Gd, and Sm metals in CN (1RECN) under visible light irradiation which was ascribed to Z-scheme formation, enhanced visible light absorption and superoxide anion radical’s involvement as the major species based on radical trapping experiments. The 1RECN photocatalyst demonstrated remarkable stability with a 3.4 % efficiency reduction after six photocatalytic degradation cycles. The effective and efficient separation and migration of photoexcited electron-hole pairs resulted in their high photodegradation activity compared to other synthesized composites and pristine CN. The fabricated composites provided an interesting perspective for a highly stable multi-elemental doped CN photocatalysts that could be employed for large scale remediation of different classes of organic pollutants.

The role of spin-lattice coupling for ultrafast changes of the magnetic order in rare earth metals

By comparing femtosecond laser-pulse-induced spin dynamics in the surface state of the rare earth metals Gd and Tb, we show that the spin polarization of valence states in both materials decays with significantly different time constants of 15 ps and 400 fs, respectively. The distinct spin polarization dynamics in Gd and Tb are opposed by similar exchange splitting dynamics in the two materials. The different time scales observed in our experiment can be attributed to weak and strong 4f spin to lattice coupling in Gd and Tb, suggesting an intimate coupling of spin polarization and 4f magnetic moment. While in Gd the lattice mainly acts as a heat sink, it contributes significantly to ultrafast demagnetization of Tb. This helps explain why all optical switching is observed in FeGd—but rarely in FeTb-based compounds.

Integrated purification of gadolinium and preparation of Gd2O3 nanoparticles by DC arc plasma

The rare-earth metal Gd plays an important role in the energy, information, and national defence fields due to its special optical, electrical, magnetic, and catalytic properties. In this study, Gd was purified by direct current (DC) arc plasma, and Gd2O3 nanoparticles were prepared via an integration method using purified Gd. The effects of arc current, melting time, gas pressure, and atmosphere on the purification of Gd by DC arc plasma were investigated. With an increase in the arc current and melting time, the rate of removal of impurities from Gd enhances. Moreover, Gd melting was conducted by H2–Ar arc plasma, which improves the impurity removal rate by increasing the H2 content. High thermal conductivity and chemical activity of the activated H atoms generated by the dissociation of H2 are the main reasons for the significant improvement in the impurity removal rate. The mechanism of Gd purification was analysed based on the above-mentioned experimental results. The as-synthesised Gd2O3 nanoparticles have a uniform spherical structure (average diameter of 32.7 nm), appropriate dispersibility, and high purity. This study provides a new strategy for the integrated purification of metals and preparation of metal/metal-based nanomaterials by DC arc plasma.

Interaction of Rare-Earth Metals and Some Perfluorinated β-Diketones.

In this work, we demonstrate the fundamental relationships between stability constants and periodic, acid-base, and structural parameters for complexes of some 1,3-diketones. The four analogues of hexafluoroacetylacetone-2-thenoyltrifluoroacetone, 2-furoyltrifluoroacetone, benzoyltrifluoroacetone, and 2-naphthyltrifluoroacetone-have been studied as chelating ligands for 16 rare-earth metals (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in aqueous solutions. Systems have been investigated spectrophotometrically using a multiwave nonlinear least-squares regression algorithm for data processing. Conditional stability constants were obtained for a wide pH region (2.0-5.4) at constant ionic strength (I = 0.5 M, NaCl). To receive the apparent ("true") equilibrium parameters, acid-base and keto-enol characteristics of the studied ligands have been described and revised for specific conditions. Dissociation constants were obtained in citrate-phosphate buffer media and protonation parameters were received in concentrated hydrochloric acid by the Cox-Yates method. The apparent formation constants for monocomplex species were obtained as thermodynamic invariants (depend only on the temperature) for each ligand and lie from 4.2 to 12.7 logarithmic units. Although the studied ligands have similar values of pKa, the stabilities of their complexes vary considerably. Systematic analysis of 64 apparent stability constants demonstrates that the force of interaction between the metals and nonsymmetric β-diketones increases as 2-furoyltrifluoroacetone < 2-thenoyltrifluoroacetone < benzoyltrifluoroacetone < 2-naphthyltrifluoroacetone. The studied ligands display varying degrees of the correlation between the periodic parameters and formation constants. Naphthyltrifluoroacetone and its complexes with heavy lanthanides exhibit a clear trend in properties with increasing ionic potential. In general, the received set of data can be described from purely electrostatic grounds within the framework of the periodic law. Spectral, keto-enol, acid-base, and complexing properties were reproduced using density functional theory modeling and explain some of the regularities discovered.

Synthesis, structural characterization and antitumor activity of six rare earth metal complexes with 8-hydroxyquinoline derivatives

The rare earth metal Gd(III), Yb(III), Lu(III), Eu(III), Tb(III) and Ho(III) complexes 1–6 with 2-((2-(pyridin-2-yl)hydrazono)methyl)quinolin-8-ol (H-L) as ligands were synthesized. The in vitro cytotoxicity assay indicated that the cytotoxicity of 1 was equivalent to cisplatin and higher than that of H-L and other complexes towards T24 tumor cells. The mechanism study indicated that 1 caused significant up-regulation of the proteins p27, p21 and p53 in T24 cells and cell cycle arrest in G2 phase. In addition, 1 induced effective T24 cells apoptosis via mitochondrial dysfunction pathway, which was indicated by changes in mitochondrial membrane potential (Δψ), reactive oxygen species (ROS), intracellular Ca2+ and the mitochondria-related proteins (including cytochrome C (Cyt C), B-cell lymphoma-2 (Bcl-2), Bcl-2-associated x (Bax) and apoptotic protease activating factor-1 (Apaf-1)). Moreover, 1 could activate caspase-3/8/9 in T24 cells. Therefore, complex 1 is a promising and potent anticancer drug candidate.

On the Formation of Electrocatalysts for Methanol and Ethanol Oxidation by the Ion Beam-Assisted Deposition of Rare-Earth Metals and Platinum on Carbon Carriers

Active layers on the surface of AVCarb® Carbon Fiber Paper P50 and Toray Carbon Fiber Paper TGP-H-060 T carbon carriers are formed by the ion-beam-assisted deposition of platinum and one of the rare-earth metals (Ce, Gd, Dy, Yb, and Ho) as an activating additive in order to obtain electrocatalysts for the direct oxidation of ethanol and methanol for fuel cells with a polymer membrane electrolyte. The deposition of metal atoms and mixing of the deposited layer with the surface of the substrate with accelerated ions of the same metal are performed from the neutral vapor fraction and the vacuum arc discharge plasma of a pulsed electric arc ion source, respectively. A distinctive feature of the obtained electrocatalysts is their higher activity in the oxidation process of more complex ethanol molecules as compared with methanol.

A simple, economical, and quick electrochemical deposition of rare-earth metal ion–doped ZnSe/FeS2 double-layer thin films with enhanced photoelectrochemical performance

Herein, various rare-earth metal (Eu, Gd, and Sm) ion-doped ZnSe/FeS2 double-layer thin films were deposited on an ITO plate via a quick and facile electrochemical deposition (ECD) method. X-ray diffraction (XRD) studies confirmed that the fabricated double-layer thin films exhibited sharp diffraction peaks which indicate their well crystalline nature. Scanning electron microscopy (SEM) showed that the double layer of ZnSe/FeS2 films was well deposited on the ITO substrate. The electron paramagnetic resonance (EPR) spectra indicated one weaker peak center at 335 mT and one high-instance very sharp peak center around 157 mT for the different metal-doped ZnSe/FeS2 double-layer thin films. From the Raman spectra, it was found that a broad peak centered at 2778 cm−1, which revealed the characteristic vibration of the ZnSe/FeS2 double layer. Electrochemical impedance spectroscopy (EIS) suggested that the Gd3+-doped ZnSe/FeS2 sample possesses a lower charge transfer resistance (Rct) of 39 Ω when compared with Eu3+- and Sm3+-doped ZnSe/FeS2 samples, demonstrating the excellent conductivity of Gd3+-doped ZnSe/FeS2 films. Moreover, the photoelectrochemical study indicates that the Gd3+-doped ZnSe/FeS2 thin film displayed a higher photocurrent than the other samples. This higher photocurrent of Gd3+-doped ZnSe/FeS2 films is mainly owing to its efficient charge separation efficiency to produce more photo-excited electron-hole pairs. Therefore, the attained Gd3+-doped ZnSe/FeS2 double-layer thin film is a promising material for photoelectrochemical device application.

Synthesis and Characterization of Pure and Rare-Earth Metal Gd Doped SnO2-CuO Nanoparticles by Co-Precipitation Method

Pure and rare-earth metal Gd doped SnO2-CuO nanoparticles were successfully prepared from the starting materials SnCl2, CuCl2 and doping element gadolinium nitrate. Pure and Gd doped SnO2-CuO were synthesized by co-precipitation method. The samples were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), UV-Vis, SEM, EDX and dielectric studies. The XRD analysis reveals that the rare-earth metal Gd dopants were substituted into rutile SnO2-CuO nanoparticles. Pure SnO2-CuO nanoparticles have an average crystallite size of 15 nm and rare-earth metal Gd doped SnO2-CuO nanoparticles have 18 nm. The average crystallite size of the sample increases when dopant was used and XRD peak intensity also increases when compared to pure SnO2-CuO nanoparticles. The optical absorption measurements exposed the nanometric size of the materials influences the energy band gap. Optical band gap was found to be 5.08 eV for pure SnO2-CuO nanoparticles and 5.14 eV for Gd doped SnO2-CuO nanoparticles. Surface morphology of pure and Gd doped SnO2-CuO nanoparticles annealed at 400 °C shows that most of the particles are rod shaped and hence it may have better sensitivity. Dielectric constant and dielectric loss decrease with increasing frequency at 100 °C and 200 °C. Doped samples show larger dielectric properties than pure SnO2-CuO nanoparticles.

Influence of rare earths alloying addition on the corrosion behavior of Zn in neutral aerated sodium chloride solution

The effect of rare earth metals (Gd, Dy, Er,) addition on the corrosion behavior of Zn has been investigated. The corrosion resistance of Zn99Gd1, Zn99Dy1, and Zn99Er1 (at%) alloys has been assessed by open circuit potential and electrochemical impedance spectroscopy (EIS) measurements carried out in a 0.1 M NaCl solution, at approximately neutral pH, without stirring and in contact with the air. For comparison, the electrochemical tests have also been carried out on unalloyed Zn. Moreover, the surface morphology and nature of the corrosion products have been investigated. The results indicated that rare earths addition significantly improves the corrosion behavior of unalloyed Zn. This improvement is most likely due to enhanced barrier properties of the corrosion products layer and additional active corrosion protection originated from the inhibiting action of the lanthanide ions entrapped as oxides/hydroxides in this surface layer.

Rare earth metal Gd influenced defect sites in N doped TiO2: Defect mediated improved charge transfer for enhanced photocatalytic hydrogen production

In this experimental studies, we report the synthesis of TiO2 co-doped by both cationic and anionic sites by simple sol-gel based method. All the prepared samples exhibit the anatase crystalline morphology however, showed lattice distortion caused by the displacement of Ti4+ sites by Gd3+. The improved visible absorption is witnessed by the Gd and N co-doping with an assured redshift in the absorption edge. The N and Gd displacement inside TiO2 lattice accompanied by the creation of OTiN and GdOTi bonds are characterized by the X-ray photoelectron spectra. The strong resonance signal by Gd4f electrons in the electron paramagnetic resonance spectroscopy further substantiate the displacement of lattice cites of TiO2 by Gd3+ ions. The longevity of the photo produced charges observed in fluorescence spectra of Gd and N co-doped TiO2 is because of the effective transfer of charges to the defect sites. The aforementioned catalysts are tested for their capacity for the H2 production from water splitting. The 2 wt% gadolinium and nitrogen co-doped TiO2 has shown 10764 μmol g−1 H2 production which is 26 times higher than the commercial Degussa P-25 catalyst. The enhanced activity for hydrogen production can be attributed to factors such as increased absorptivity under visible light and effective charge carrier separation.

Magnetic phase diagrams of Gd-H, Tb-H, Dy-H systems

We study the impact of hydrogen impurity on the magnetic phase transition temperatures of the high purity rare-earth metals Gd, Tb and Dy. Prior to hydrogenation, the rare earths were purified by the vacuum distillation method. Hydrogenation was carried out using a Sievert-type apparatus. Magnetic phase diagrams were constructed based on the thermomagnetic analysis.

R2Co3-xSix (R = Pr, Nd, Sm, Gd) and R2Ni3-xSix (R = Gd-Er), new series of La2Ni3-type phases

In this study, we have expanded our previous work on the Gd2(Co3-xSix) solid solution to form the family of R2(T3-xSix) compounds with a wide range of the rare earth metals (Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) by variation of the composition and, where necessary, the transition element (Co and Ni). We report the crystallographic and the magnetic properties of this La2Ni3-type series. The R2Co3-xSix compounds with R = Pr, Nd, Sm and Gd, undergo ferro- or ferrimagnetic transitions at TC ranging from 64 K (Nd) to 338 K (Gd) and the R2Ni3-xSix phases with R = Gd-Er display ferromagnetic order below TC from 96 K (Gd) to 7 K (Er).

Effects of rare earth doping on multi-core iron oxide nanoparticles properties

Abstract New multi-core iron oxide magnetic nanoparticles doped with rare earth metals (Gd, Eu) were obtained by a one step synthesis procedure using a solvothermal method for potential biomedical applications. The obtained clusters were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX), X-ray photoelectron spectroscopy (XPS) and magnetization measurements. They possess high colloidal stability, a saturation magnetization of up to 52 emu/g, and nearly spherical shape. The presence of rare earth ions in the obtained samples was confirmed by EDX and XPS. XRD analysis proved the homogeneous distribution of the trivalent rare earth ions in the inverse-spinel structure of magnetite and the increase of crystal strain upon doping the samples. XPS study reveals the valence state and the cation distribution on the octahedral and tetrahedral sites of the analysed samples. The observed shift of the XPS valence band spectra maximum in the direction of higher binding energies after rare earth doping, as well as theoretical valence band calculations prove the presence of Gd and Eu ions in octahedral sites. The blood protein adsorption ability of the obtained samples surface, the most important factor of the interaction between biomaterials and body fluids, was assessed by interaction with bovine serum albumin (BSA). The rare earth doped clusters surface show higher afinity for binding BSA. In vitro cytotoxicity test results for the studied samples showed no cytotoxicity in low and medium doses, establishing a potential perspective for rare earth doped MNC to facilitate multiple therapies in a single formulation for cancer theranostics.

PEG-functionalized ionic liquids: A class of liquid materials for highly efficient extraction of rare earth metals from aqueous solutions

Recycling of rare earth metals is important for their supply risk in the future. In this work, a greener and highly efficient liquid-liquid extraction strategy is presented for rare earth metals from aqueous solution with PEG-functionalized ionic liquids. The factors influencing the solvent extraction process such as phase volume ratio, equilibrium time, pH value of aqueous phase, alkyl chain length of the ionic liquids and temperature of the system were investigated systematically. It was found that under optimal conditions, the single-step extraction efficiency was >96.8% for the studied 11 kinds of rare earth metal ions Sc(III), La(III), Ce(III), Y(III), Nd(III), Sm(III), Gd(III), Dy(III), Ho(III), Yb(III) and Lu(III). After the extraction, about 100% of the rare earth metals could be stripped from the ionic liquids phases by using dilute aqueous oxalic acid, and the ionic liquids would be recovered and reused in the next extraction process. In addition, the extraction mechanism was investigated in some details, and an ion pair association mechanism was suggested. Since the extraction procedure was performed without saponification, addition of extra extractant, organic diluents or salt, the approach described here has the potential to be used as a sustainable strategy for the separation and enrichment of rare earths from complex matrixes.