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We report the real-valued static and complex-valued quasi-static anisotropic permittivity parameters of rare-earth scandate orthorhombic single crystal GdScO3 (GSO), TbScO3 (TSO), and DyScO3 (DSO). Employing continuous-wave terahertz spectroscopy (0.2–1 THz), the complex permittivity was extracted using an anisotropic ambient-film-ambient model. Data obtained from multiple samples of the same oxides and different surface cuts were analyzed simultaneously. The zero-frequency limit of the modeled data indicates that at room temperature the real part of the dielectric tensor components for GSO are ɛa = 22.7, ɛb = 19.3, and ɛc = 28.1; for DSO, ɛa = 20.3, ɛb = 17.4, and ɛc = 31.1; and for TSO, ɛa = 21.6, ɛb = 18.1, and ɛc = 30.3, with a, b, and c crystallographic axes constituting the principal directions for the permittivity tensor. These results are in excellent agreement with expectations from theoretical computations and with scarcely available data from previous experimental studies. Furthermore, our results evidence a noticeable attenuation, which increases with frequency, and are very significant especially at the higher frequency end of the measurement and along the c-direction in all samples. We suggest the attenuation is most likely caused by the onset of absorption due to long-wavelength active optical phonon modes. These results are important for electronic and potential sub-terahertz applications (e.g., quarter-wave plate) benefiting from the large index contrast along different directions in these materials. [ABSTRACT FROM AUTHOR]

Rare-earth doped materials are of immense interest for their potential applications in linear and nonlinear photonics. There is also intense interest in sub-nanometer gold clusters due to their enhanced stability and unique optical, magnetic, and catalytic properties. To leverage their emergent properties, here we report a systematic study of the geometries, stability, electronic, magnetic, and linear and nonlinear optical properties of Au5RE (RE = Sc, Y, La–Lu) clusters using density-functional theory. Several low-energy isomers consisting of planar or non-planar configurations are identified. For most doped clusters, the non-planar configuration is energetically favored. In the case of La-, Pm-, Gd-, and Ho-doped clusters, a competition between planar and non-planar isomers is predicted. A distinct preference for the planar configuration is predicted for Au5Eu, Au5Sm, Au5Tb, Au5Tm, and Au5Yb. The distinction between the planar and non-planar configurations is highlighted by the calculated highest frequencies, with the stretching mode of the non-planar configuration predicted to be stiffer than the planar configuration. The bonding analysis reveals the dominance of the RE-d orbitals in the formation of frontier molecular orbitals, which, in turn, facilitates retaining the magnetic characteristics governed by RE-f orbitals, preventing spin-quenching of rare earths in the doped clusters. In addition, the doped clusters exhibit small energy gaps between frontier orbitals, large dipole moments, and enhanced hyperpolarizability compared to the host cluster. [ABSTRACT FROM AUTHOR]

The article presents the study of the magnetocaloric effect (MCE) for the rhombohedral Laves phase of Pr 2 Rh 3 Ge, which shows a magnetic order below T C = 8.5 K. We have established that the compound exhibits a continuous second-order type of transition which was demonstrated and confirmed by several different techniques, mainly by analyzing universal curves of normalized entropy change as a function of scaled temperature. The observed MCE, in our opinion, is a consequence of an indirect exchange coupling between the magnetic sublattices of the rare earth ions, which, however, does not exclude the potential contribution of sublattice-containing transition metals. In this paper, the procedure to evaluate the MCE from magnetization and specific heat data is described. As a result, important parameters such as the isothermal magnetic entropy change (Δ S M), adiabatic temperature change (Δ T a d ), relative cooling power (RCP), and the temperature averaged entropy change (TEC) were determined. The highest values of − Δ S M , Δ T a d , and RCP for a field change (Δ μ 0 H) of 5 T at T C are 5.96 J/kg K, 3.87 K, and 72.62 J/kg, respectively. These results obtained for Pr 2 Rh 3 Ge seem to be, however, low compared to the values obtained for the rhombohedral Laves phases, belonging to the group of ternary germanides RE 2 Rh 3 Ge containing heavy rare earth metals (RE = Gd, Tb, Ho, and Er). Nevertheless, we believe that the results presented in this work extend and complement the current knowledge on the magnetocaloric properties of this family of materials. [ABSTRACT FROM AUTHOR]

Rare-earth-nanomaterials (RE-NMs) have surged to the forefront of cutting-edge research, captivating scientists and engineers alike with their unprecedented potential and transformative applications with the primary sources for these materials being monazite (lanthanide concentrate) used to produce Rare Earth Oxides (REOs). RE-NMs are nanomaterials derived from the 17 Rare Earth Elements (REEs), encompassing the 15 lanthanides (∼La, Ce, Nd, Ho, Pr, Eu, Tm, Sm, Yb, Er, Lu, Gd, Tb, Pm , and Dy), Sc and Y are employed in advanced technologies for their unique nanoscale properties in applications such as electronics, magnets and catalysts. Rare earth elements are classified into three distinct categories: light rare earth elements (LREE), medium rare earth elements (MREE), and heavy rare earth elements (HREE). These elements are prized for their unique electronic configurations, metal radii and atomic numbers, which endow them with extraordinary structural, electronic, chemical bonding, optical and electrical properties. Throughout the ages, there has been a tremendous and cross-disciplinary fascination with these exceptional materials, exploring their myriad applications from active doping and co-doping to tri-doping and innovative composites, all driven by the quest for groundbreaking solutions in energy conversion and storage towards a more sustainable world. This critical review provides a broad overview of recent progress in the design and development of rare-earth-based nanomaterials. It addresses: (1) the discovery and sources of rare-earth-based nanomaterials, (2) methods for synthesizing RE-NMs and fabricating RE-NM thin films and (3) the exploration of RE-NMs in applications including solar cells, electrochemical devices and supercapacitors, along with their diverse applications across multiple fields. To conclude, this review summarizes current advancements and offers stimulating perspectives on the challenges and future research directions in the realm of RE-NMs. This review aims to open new research pathways for developing recycling methods and cutting-edge renewable energy nanomaterials (RE-NMs) from residue waste. Utilizing these materials in renewable energy applications could minimize environmental impact and pave the way for innovative uses of photocatalysts, solar cells and supercapacitors contributing to sustainable energy solutions in the future. [Display omitted] • Exploiting RE-NMs shows promise for modifying and treating nanomaterials. • Studying RE-NMs impact on structural, optical and electronic properties. • RE-NMs enhance solar cells, electrochemical reactions and improve supercapacitors. [ABSTRACT FROM AUTHOR]

Wildfires impact a large and increasing proportion of the Earth's surface. With documented soil surface temperatures of up to ∼850 °C, wildfires may fundamentally alter the mineralogy and geochemistry of soils and regolith, more conventionally thought to be dominated by low temperature weathering processes. Here we use an experimental approach to test the effect of temperature on the formation of pyrogenic minerals, and on the distribution and mobility of major, trace and rare earth elements following post-fire chemical weathering. We focus on ferruginous nodules, common Fe-oxide cemented components of soils, which transform from non-magnetic to maghemite-bearing, magnetic nodules under wildfire conditions. These transformations provide a valuable record of fire impacts and facilitate the study of thermal processes and element mobility. Our results show heating produces a typical pyrogenic mineral assemblage of hematite, maghemite, metakaolin and transition alumina. At 900 °C the high temperature Fe 2 O 3 polymorph luogufengite forms, which has never been reported in natural fire-affected substrates and therefore places an upper boundary on palaeowildfire temperatures at the soil-fire interface. Chemical leaching, employed to simulate the impacts of post-fire weathering, demonstrates that formation and subsequent breakdown of these pyrogenic minerals results in increased mobility of several elements including Li, Si, Sc, Cr, Co, Cu, Zn, Rb, Cs, La, Pb and U. Further, we propose that incongruent dissolution of pyrogenic metakaolin may be responsible for the formation of fusic material, an aluminous cement commonly found in soils. We conclude by discussing the significance of these results for the release of potentially toxic metals following a fire, identify trace elements that have the greatest potential to be used as palaeowildfire geochemical proxies (decreased alkali metal concentrations, decreased U/Th ratios, and decreased La compared to other rare earth elements), and the potential impact of wildfire on global geochemical cycles. [ABSTRACT FROM AUTHOR]

To investigate the potential of rare earth oxide structural ceramics for high-temperature insulation applications, we introduced aerogel structures into Yb 2 SiO 5 ceramics. In this study, the pure Yb 2 SiO 5 ceramic aerogels were successfully prepared by calcination using formamide as a gelling agent, the sol-gel method, and the CO 2 supercritical drying method. The results indicate that the Yb 2 SiO 5 ceramic aerogel exhibits exceptional structural and phase stability at a temperature of 1400 °C. In addition, we have developed Yb 2 SiO 5 ceramic aerogel composites reinforced with aluminosilicate fiber cotton, which exhibit low density (228.77 kg m−3) and low thermal conductivity (0.038 W m−1 K−1 at 25 °C, 0.102 W m−1 K−1 at 1000 °C). The back temperature of the 10 mm thick composites is only 285 °C after exposure to a butane blowtorch flame at 1300 °C for 600 s. This demonstrates its excellent high-temperature insulation performance. This work can provide a basis for further design and preparation of oxide ceramic high-temperature thermal protection materials with controllable morphology and properties. [ABSTRACT FROM AUTHOR]

This study investigates the effect of rare earth oxide CeO 2 on the physical properties of ceramsite and its efficiency in treating ammonia-nitrogen wastewater. Ceramsite was prepared from solid waste with 10 % coal gangue added as a pore-forming agent. Ceramsite sample I with CeO 2 and sample II without CeO 2 were prepared using pure reagents. The process parameters for both samples were optimized using an orthogonal test. Additionally, the effects of CeO 2 on ceramsite performance and the treatment of ammonia-nitrogen wastewater were studied, and the adsorption mechanism of CeO 2 on ammonia-nitrogen wastewater was clarified. The process parameters for preparing ceramsite sample Ⅰ were: preheating for 30 min at 600 °C, followed by roasting for 20 min at 1090 °C. The parameters for preparing ceramsite sample Ⅱ were: preheating for 30 min at 600 °C, followed by roasting time for 15 min at 1090 °C. The presence of CeO 2 increased the porosity of the ceramsite by 0.89 % and the specific surface area by 0.66 m2/g. Under neutral environmental conditions of water samples, CeO 2 increased the removal rate of ammonia nitrogen by 1.85 %. Ceramsite has a high porosity and specific surface area, indicating that it has abundant internal pores, a large contact area with ammonia-nitrogen, a strong ability to remove ammonia nitrogen, and resistance to erosion and water flow shear, which are conducive to the treatment of ammonia-nitrogen wastewater. [ABSTRACT FROM AUTHOR]

By manipulating the work function, the dissipation of thermal energy on the material surface can be regulated through Electron Transpiration Cooling (ETC) mechanism. The doping of rare-earth oxide serves as an effective approach for reducing the work function, whereas there is still a lack of comprehensive research into the microstructural morphology of the rare-earth oxides and their correlations with the modifications of the work functions. This study investigates the detailed microscopical structure of Gd 2 O 3 in the ultrahigh-temperature ceramic system (ZrB 2 -20 vol%SiC). Semi-quantitative composition analyses based on X-ray photoelectron spectra indicate that an increased doping concentration of Gd 2 O 3 is beneficial for the formation of a single solid-state Gd 0.18 Zr 0.82 O 1.91 phase of ZrB 2 -SiC system. Atomic-scale scanning transmission electron microscopy (STEM) analyses suggest that Gd 2 O 3 is enriched at the interfaces between SiC and ZrB 2 matrix with a nanoscale fibrous morphology composed of alternated Gd 2 O 3 crystals and pores, rendering a continuous microstructure throughout the entire system. This peculiar microstructural morphology is anticipated to facilitate its diffusion along the grain boundary and the formation of Gd 2 O 3 nanolayers at the surface region below the melting points of the ceramic matrix, which can efficiently lower the material work function and reduce the emission energy of the surface electrons during thermal emission through ETC mechanism. The composite with 10 vol% Gd 2 O 3 induces a reduction of the averaged work function of ∼0.49 eV before preforming the thermionic emission experiments. Our results provide valuable insights into the impacts of rare-earth oxide on the ZrB 2 -SiC matrix, as well as shed light on the feasibility of the ETC mechanism through the efficient design of thermal protection materials. [ABSTRACT FROM AUTHOR]

The healing of wounds is still a difficult clinical issue, and effective wound management is necessary to promote wound healing. Fabrication of highly developed dressings for wounds exhibiting biologically active properties and possessing favorable mechanical characteristics to accelerate the period of healing to avoid sideways bacterial infection. Hyaluronic acid (HA) inserted with loaded metal oxides such as silver phosphate (Ag3(PO4)), CNT and samarium oxide (Sm2O3) by film casting technique. The prepared films were examined by XRD, SEM, FTIR, and TGA. The surface topography showed a rough surface with low porosity for pure HA, while the addition of nanoparticles caused an incredible increase in the roughness with pores in diameter of 4–15 µm. The smooth surface appeared due to the addition of carbon nanotubes (CNT) and the mixing of the HA with polyvinyl alcohol (PVA). The contact angle was determined with water drops to determine the wettability of the prepared films, and it showed different changes varying between 67.72° for pure HA and then increased to 73.33° with the addition of Ag3(PO4), while the addition of Sm2O3 reduced the angle to 54.76° and 46.59° with mixing the ratios of nanoparticles. On the other hand, the Ag3(PO4)/Sm2O3/CNT@PVA/HA film represented a slight increase in the angle to 53.77° which has a hydrophilic tendency. The antibacterial test was done, and it was shown that the inhibition zone reached 20.5 ± 1.5 and 17.5 ± 1.5 against E. coli and S. aureus, respectively, for Ag3(PO4)@HA. The generated data display that the biological behavior of the mentioned nanocomposites (NCs) is promising. [ABSTRACT FROM AUTHOR]

Five new lanthanide complexes {[Sm(H2L)(H2O)4(Cl)]⋅H2O⋅Cl}n (1), {[Eu(H2L)(H2O)4Cl]⋅Cl}n (2), {[La(H2L)(H2O)4Cl]⋅Cl}n (3), {[Pr(H2L)(H2O)4Cl]⋅Cl}n (4), {[Ce(H2L)(H2O)4Cl]⋅Cl}n (5) (H3L = 2‐hydroxy‐5‐(5‐(hydroxy‐λ2‐methoxy)‐1H‐benzo[d]imidazole‐5‐carboxylic acid) were successfully synthesized under solvothermal method. 1 exhibits a two‐dimensional (2D) network structure, whereas 2–5 feature one‐dimensional (1D) chain structure. The fluorescence investigations demonstrated that 1–5 could be the fluorescent sensor for nitrobenzene (NB) and Fe(III) ions with high selectivity, sensitivity, and low detection limits. Furthermore, 1–5 displayed the good adsorption to anionic dye Congo red (CR), and the adsorption capacities were 140.5, 206.5, 212.5, 111.5, and 211.5 mg·g−1, respectively. [ABSTRACT FROM AUTHOR]

The exploitation of deep-eutectic solvents (DESs) offered a potential substitute for water-based solutions when it came to leaching REEs from phosphogypsum (PG). The REEs leachate from PG obtained by DES which comprised choline chloride (ChCl) and diglycolic acid (DGA) or lactic acid (LA). The data offered a successful method for REEs leaching by DES ChCl:LA. The optimal leaching conditions included 150 min, 70°C, ChCl:LA 1:2 molar ratio of 800 rpm, a 15:1 L/S ratio, and 15% additional water. Cyanex 923 was used to assess REEs extraction from DES leachate. The best parameters were 900 rpm, 0.8 M Cyanex/toluene at 25°C, with 15 min extraction time and 1/1 A/O ratio. The REEs were stripped from the REEs/Cyanex after equilibrating for 20 minutes using 0.7 M citric acid, 1/2 A/O ratio, and 1000 rpm at 25°C. The RE ions precipitated from the obtained stripping solution by 30% oxalic acid and pH 1. The RE oxalate was precipitated and then burned at 700°C to gain RE oxide. The RE oxide powder was subjected to analysis to determine the REEs; it was possible to determine that the REEs were 80.98% in RE oxide concentrate, resulting in a purity of 94.76%. [ABSTRACT FROM AUTHOR]

Borosilicate glasses are the primary waste forms for the industrial immobilization of high‐level liquid waste. Yet, the compositional variation of waste glasses can form the diopside phase, which can be detrimental to the melting process and the properties of the final glass products. This study prepared simulated waste glasses with variable contents of alkaline earth metals, boron, transition metals, and rare earth metal oxide and subjected them to heat treatments. The effect of the compositional variation on the diopside crystallization behavior was explored using differential scanning calorimetry, X‐ray diffraction, optical microscopy, and scanning electron microscopy‐energy dispersive spectroscopy. The results revealed that the average size of diopside crystals was proportional to the square root of the heat treatment durations. Increased contents of alkaline earth and transition metal oxides could contribute to the growth of diopside crystals, while boron oxide tended to inhibit it. Finally, a prediction model correlating the average crystal size, compositional variation, and heat treatment durations was discussed. [ABSTRACT FROM AUTHOR]

Radioisotope thermoelectric generators (RTGs) are deal energy supply devices for deep space and deep-sea exploration, and it is also the energy core of the operation of the working equipment. Except for 238Pu (Plutonium), 241Am (Americium) was also used as a nuclide in the radioactive energy system for future space exploration missions. In this work, neodymium oxide (Nd 2 O 3) was used as analogues for Am 2 O 3. Cold-press-and-sinter methods was used. Different particle parameters (morphology, size, and crystal structure) and synthesized parameters of Nd 2 O 3 were investigated. The synthesized powders contained lath-shaped particles, and batches with different particle sizes and microscopic topography were made and sintered. The results show that the optimal precipitation temperature of Nd 2 O 3 is 25 °C. The optimal thermal decomposition temperature range is 900 °C to 1100 °C, and the optimal thermal decomposition heating rate is 10 °C min−1. The samples of Nd 2 O 3 pellets without cracking is obtained with relative density of 85%–90 %. The Vickers hardness of Nd 2 O 3 pellets was also studied. This paper provides an important scientific guiding significance for the cold-press-and-sinter of radioisotope 241Am batteries in the future. [ABSTRACT FROM AUTHOR]

Exploration of secondary resources for isolation of valuable constituents, such as rare earth elements (REEs) and trace elements (TEs), is of importance owing to the need to identify new domestic sources and reduce reliance on imports. The present study systematically discusses the distribution of REEs and TEs in core samples from the coal block of Bhalukasba Surni {(B1(125 m)-B9 (409 m)} located in Rajmahal coalfield, Jharkhand, India, which has not been investigated previously for its geochemistry. The studied coal samples were found to be enriched in TEs whose abundances were in the order of Mn > Mo > Zr > Ni > Cr > V > Cu > Zn > Pb, and REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb, Lu) along with Sc and Y. The average concentration of REEs with yttrium (ΣREY) on an ash basis was 528 ppm, which is significantly higher than the world average for coal ash (435 ppm). Of the samples investigated, B3 (182–184 m) and B8 (396–399 m) demonstrated relatively higher concentrations of potentially economic elements, with B3 containing a higher proportion of middle to heavy REEs Gd, Dy, Ho and Er, and B8 showing relative enrichment in Nd and Y. On dry whole coal basis, B6 (275–278 m) showed a considerably higher concentration of Ge (55 ppm) than other samples, whereas the concentration of Zr varied in the range of 90–160 ppm in the whole coal block. X-ray diffraction studies revealed the presence of quartz, keatite, hematite, zircon, anatase and orthoclase in the coal ash samples prepared at 815 °C. REEs exhibited prominent positive correlation with Al2O3 (0.4 < r > 0.9) which is supportive of their residence in primary clay minerals such as kaolinite and illite-smectite. Additionally, a positive correlation of REEs with P2O5 (0.4 < r > 0.9) suggests their association with phosphate minerals (such as monazite, xenotime, apatite). Positive correlation with TiO2 (r > 0.7) corroborates the possible association of REEs with anatase. The morphology of the coal ash samples viewed in SEM showed the presence of Al2O3 and SiO2 enriched irregular-sponge particles likely derived from partly-fused clay minerals, which accounted for the lower extent of REE encapsulation. The Bhalukasba Surni coal block is potentially of economic importance due to its enrichment in Ge, Zr, and the REEs. Highlights: A systematic study on the distribution of REEs and TEs in the coal block of Bhalukasba Surni in Rajmahal coalfield, Jharkhand, India was performed. The average concentration of ΣREY on an ash basis was 528 ppm as compared to the world average of 435 ppm. Enrichment of trace elements followed the order of Mn > Mo > Zr > Ni > Cr > V > Cu > Zn > Pb. X-ray diffraction studies revealed the presence of quartz, keatite, hematite, zircon, anatase and orthoclase in the coal ash samples prepared at 815 °C. [ABSTRACT FROM AUTHOR]

ZnO linear resistors, due to its excellent performance, are widely used in numerous industries and gradually replacing traditional conductive resistors, presenting a broad prospect for application. To study the effects of lanthanide oxides on the microstructure and electrical properties of ZnO-based linear resistors, this paper prepared Dy 2 O 3 -doped ZnO-Al 2 O 3 -TiO 2 -NiO based linear resistors using a solid-state sintering method. The results showed that proper doping of Dy 2 O 3 could inhibit the growth of ZnO grains, leading to more uniform grain growth. Additionally, doped with appropriate amount of Dy 2 O 3 could enhance the linear performance of ZnO linear resistors, reduce the grain boundary barrier height (φ b), and decrease dielectric loss. Linear resistors with nonlinearity coefficient (α) of 1.07, grain boundary barrier height (φ b) of 0.0934 eV and resistance-temperature coefficient (α T) of −5.39 × 10−3/°C were obtained. The doping of Dy 2 O 3 could improve the comprehensive performance of ZnO linear resistors, making the fabricated ZnO linear resistors are more suitable for working in high frequency electric fields. The study and analysis of Dy 2 O 3 doped ZnO linear resistors are of significant importance for the preparation of high performance ZnO linear resistors. [ABSTRACT FROM AUTHOR]

In this paper, erbium-doped gadolinium oxide rare earth oxide nanoparticles (Gd 2 O 3 :Er3+) with good light absorption capacity from the visible to the infrared region were prepared by polyol method, and then compounded with TiO 2 by hydrothermal method. SEM, TEM, XPS, UV–vis and electrochemical workstation were used to study the morphology, structure, UV–vis light absorption and photoelectrochemical (PEC) properties of Gd 2 O 3 :Er3+/TiO 2. The results showed that the Gd 2 O 3 :Er3+ spherical nanoparticles with a particle size of about 15 nm were uniformly distributed on the surface of the TiO 2 nanorod array, and the Gd 2 O 3 :Er3+/TiO 2 nanocomposites had good light absorption capacity in the infrared region. Furthermore, the photocurrent densities of Gd 2 O 3 /TiO 2 and Gd 2 O 3 :Er3+/TiO 2 were 2.08 and 2.75 times higher than those of TiO 2 , respectively, manifesting that the broadening of infrared light absorption can improve the PEC property of TiO 2. Meanwhile, the DFT calculation results showed that the energy band of Gd 2 O 3 :Er3+/TiO 2 was significantly narrower than that of TiO 2 , indicating that Gd 2 O 3 :Er3+/TiO 2 had a redshift phenomenon of UV–vis absorption. The calculation results of state density showed that the f orbital of Gd 2 O 3 :Er3+ intersected with the d orbital of TiO 2 , indicating that there is an electron transfer between Gd 2 O 3 :Er3+ and TiO 2. Erbium-doped gadolinium oxide rare earth oxide nanoparticles (Gd 2 O 3 :Er3+) with good light absorption capacity from the visible to the infrared region were prepared by polyol method, and then compounded with TiO 2 by hydrothermal method. Both theoretical and experimental results confirmed the extension of optical absorption into the infrared range and the charge transfer from Gd 2 O 3 :Er3+ to the TiO 2 surface, facilitating electron-hole separation and reducing charge recombination rate. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel high-entropy oxide, Sm 2 Gd 0.25 Dy 0.25 Er 0.25 Yb 0.25 TaO 7 , was synthesized via Sol-Gel and high-temperature calcining method. The powder and bulk specimen for Sm 2 Gd 0.25 Dy 0.25 Er 0.25 Yb 0.25 TaO 7 were characterized, and its thermophysical performances were measured. The researching conclusions indicate that the synthesized nano-powder is very pure, and the block specimen has a sole pyrochlore structure, densified microstructure, and uniform distribution of elements. The low thermal conductivity is ascribed to phonon scattering stemmed from the ionic size and atomic mass disorders derived from multi-component addition. The high lattice-energy leads to a relatively low thermal expansion coefficient, which satisfies the demand of thermal barrier coating. The Sm 2 Gd 0.25 Dy 0.25 Er 0.25 Yb 0.25 TaO 7 oxide also maintains outstanding phase steadiness up to 1200 °C. [ABSTRACT FROM AUTHOR]

Layered Ruddlesden-Popper (RP) neodymium nickelate oxide, Nd 2 NiO 4+δ , is considered a potential cathode material in solid oxide fuel cells. In this study, the equilibrium properties of NNO were investigated by using quasi-equilibrium oxygen release to contract the isothermal equilibrium diagram "lg pO 2 – (4+δ) – T". Furthermore, the kinetic properties of NNO were studied by oxygen partial pressure relaxation to determine the equilibrium oxygen exchange rate (R 0), chemical diffusion coefficient in oxide (D chem), and surface exchange rate constant (k chem). The Brønsted-Evans-Polanyi-type linear free energy relationship was shown to exist between the standard Gibbs energy of the reaction and the activation energy of the reaction rate constant. [ABSTRACT FROM AUTHOR]

This study reports on the synthesis of lanthanide oxides triply doped titania, forming a novel hetero-system known as (Sm3+/Eu3+/Tm3+)-TiO 2. An environmentally friendly sol gel method was used to synthesize the energy-efficient (Sm3+/Eu3+/Tm3+)-TiO 2 , and thin films were deposited by spin coating. Electrode and solar cell devices were fabricated under ambient conditions, and rare earth doping enhanced the opto-electronic aspects of the host by narrowing the band gap up to 3.92, 3.85, and 3.56 eV. Particle sizes for the pure and doped materials were 85.15 and 82.72 nm, respectively. With a specific capacitance of 667.34 F g−1, the lanthanide-doped ornamented nickel foam electrode outperformed the pristine electrode, which had a specific capacitance of 169.59 F g−1. Moreover, this electrode exhibited tiny equivalent series resistance (R s) of 0.13 Ω, indicating quicker response kinetics at the interface, in addition to its electrical double layer capacitance behavior. Electrochemical studies revealed that (Sm3+/Eu3+/Tm3+)-TiO 2 semiconductor has a high specific power density of 8157.03 W kg−1, compared to 4079.73 W kg−1 for undoped titania. This improved specific power density demonstrates its suitability for practical scale applications. The produced materials were an excellent HER electro-catalyst with remarkably lower overpotential and Tafel slopes i.e., of 137 mV and 87.6 mV dec−1, in a respective manner, in comparison to the reference TiO 2 with 147 mV and 104.5 mV dec−1, respectively. The electro-catalyst's response to the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) was enhanced upon lanthanide doping. Additionally, this substance successfully retrieved electrons from a perovskite solar cell device, achieving efficiency levels of 16.49 and 16.75 % in both forward and reverse bias with fill factor increase. [ABSTRACT FROM AUTHOR]

Mg-based amorphous alloys have broad applications due to disordered atomic structure, thermal stability, crystallinity, low elastic modulus and high strength. In the present study, Mg–Ni–Gd–Yb–Ag alloys were prepared by vacuum arc melting combined with copper roll melt spinning. The addition of trace amounts of ytterbium (Yb) improved the corrosion resistance of Mg73-XNi15Gd10YbXAg2 (x = 2,4,6,8 at.%). Electrochemical experiments, immersion tests and analysis of corrosion products by XPS and EDS showed that Mg67Ni15Gd10Yb6Ag2 exhibited the best corrosion resistance with an Ecorr of − 968 mV and an Icorr of 5.93 µA/cm2. The superior corrosion performance was attributed to the presence of corrosion passivation films comprising MgO, Mg(OH)2, Ni(OH)2, Ag2O, AgCl, Ca5(PO4)3(OH), as well as rare-earth oxides Gd2O3 and Yb2O3. These compounds efficiently shield the matrix, and the microstructure corrosion mechanism of Mg–Ni–Gd–Yb–Ag involves a cyclic process that includes surface film layer dissolution, matrix corrosion and film layer regeneration, leading to oxide attachment. The addition of the appropriate amount of rare-earth element Yb to Mg-based amorphous alloys can improve the corrosion resistance, thereby increasing the application prospects of alloys. [ABSTRACT FROM AUTHOR]

Mn‐based oxides are broadly prospected cathode materials for aqueous Zn‐ion batteries (AZIBs) due to their rich abundance, low cost, and plentiful valence states. However, the further development of Mn‐based oxides is severely restricted by the dissolution of active materials and poor structural stability. Herein, hollow octahedral Pr6O11‐Mn2O3 (denoted as PrO‐MnO) heterostructures are developed through a facile metal–organic framework‐engaged templating approach, which realizes boosted Zn ion storage performance. Pr6O11 can not only effectively suppress the dissolution of Mn to stabilize Mn2O3 but also induce interfacial charge rearrangement and promote electron/ion transfer, contributing to the improved electrochemical activity and stability of PrO‐MnO. Moreover, the rationally designed hollow nanostructure offers sufficient active sites and facilitates the reaction kinetics. As expected, the PrO‐MnO cathode exhibits excellent rate and cycling performance with a high reversible capacity of 140.8 mAh g−1 after 2000 cycles at 1 A g−1, outperforming the Mn2O3 cathode. [ABSTRACT FROM AUTHOR]

The study on phosphors‐converted white light‐emitting diodes (pc‐WLEDs) using lead‐free double perovskites (DPs) as single‐component white phosphors is widely concerned. However, the photoluminescence quantum yields (PLQY) of white luminescence and color rendering index (CRI) of WLED are not satisfactory. Herein, a new Sb/Ho: Cs2Na0.9Ag0.1(In/Bi)Cl6 single‐component white phosphor with the highest PLQY of 93% and a record CRI of 97.4 is reported. Experimental data and theoretical calculations evidence that in addition to broadband yellow emission of the self‐trapped exciton (STE) recombination, the material also exhibits blue emission from Sb3+: 3P1→1S0 transition and red one assigned to Ho3+: 5F5→5I8 transition. Steady‐state and time‐resolved PL spectra verify the existence of two energy transfer channels from both Sb3+ and STE to Ho3+ dopants. As a demo, Sb/Ho: Cs2Na0.9Ag0.1(In/Bi) Cl6‐based WLED is constructed, showing excellent comprehensive optical performance with specially improved saturation red index R9 and blue one R12. This work provides a novel single‐component rare‐earth doped DP white phosphor for high CRI full‐spectrum solid‐state lighting. [ABSTRACT FROM AUTHOR]

Ethylene propylene diene monomer (EPDM) rubber is used in critical sectors such as national defense, military, and aerospace. However, it has performance limitations under high temperatures, affecting its dynamic mechanical properties, creep, and stress relaxation. To overcome these limitations, rare earth cerium oxide (CeO2) was incorporated as a filler into EPDM in this study, which enhances its properties and makes it suitable for the demanding applications. It could be seen that the CeO2‐enriched EPDM has significantly improved mechanical characteristics at elevated temperatures. The Young's modulus of CeO2‐enriched EPDM increased by about 100 %, while the energy storage modulus reaches a maximum increase of around 140 % at 165 °C. The addition of CeO2 improves its damping properties, provides better creep and stress relaxation resistance, and results in greater residual strain recovery. At room temperature, the impact on the stress relaxation rate at 50 % strain is minimal for the material EPDM, and it is almost negligible for the material EPDM/CeO2.These findings demonstrate that CeO2‐enriched EPDM has enhanced performance under high‐temperature conditions. Under elevated temperature conditions, EPDM enriched with CeO2 exhibits enhanced mechanical properties, superior creep resistance, and stable stress relaxation behavior, rendering it more adept at withstanding the rigorous conditions encountered in aerospace applications. [ABSTRACT FROM AUTHOR]

Bright yellow upconversion emission spectra at 595 nm were investigated in Nd3+ ions doped gadolinium orthovanadate (GdVO 4) single crystals. 556-fold enhancement of the intensity of upconversion emission at 595 nm was investigated at the sample temperature of 400 °C, which followed the exponential increase with temperature. The lg-lg relationships of the detected upconversion emission spectra and the input pumping laser were discussed, which dropped to 2.28 at high temperature from 5.98 at low temperature and implied fewer photons are required at higher temperatures. Thermal phonon-assisted excitation and electron-phonon coupling activities played important roles in the one photon upconversion emission excited by the laser centered at 1064 nm, and over 3700-fold enhancement of the emission peaks at 756 nm was observed. The finding in this work provides thermal stability analysis in Nd3+ ions doped laser materials and expands rare earth ions upconversion mechanisms. [ABSTRACT FROM AUTHOR]

Doped cerium oxides are technologically relevant materials and used as electrolytes in intermediate temperature solid oxide fuel cells. An important issue for these materials is the reduction of ceria at low oxygen partial pressures which leads to mixed ionic electronic conduction. In the present work, reduction behaviour in Ce 0.8 Nd 0.2 O 1.9-δ is examined under inert and strongly reducing conditions. Even under inert conditions, ca. 3.5 % of the Ce is redox active up to around 800 °C, which appears to be correlated with non-linear behaviour in the Arrhenius plot of conductivity and thermal expansion of the lattice. Under more strongly reducing conditions, a secondary partial reduced phase is formed related to triclinic Ce 11 O 20 , which introduces significant electronic conductivity into the system. The dynamics of the re-oxidation process are examined using X-ray powder diffraction and electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Identifying geothermal reservoir rock types is fundamental in geothermal exploration, but the absence of active surface geothermal manifestations (especially hot springs) in blind geothermal systems makes this identification difficult. Nevertheless, blind geothermal systems may develop early-formed hot-spring deposits. As (bio-) chemical precipitate, these deposits may retain geochemical signatures of spring waters and thus provide insights into reservoir rock types. To assess their geothermal implications, the 87Sr/86Sr and rare earth elements + yttrium (REE + Y) characteristics of hot-spring deposits in two geothermal systems were investigated and compared with those of their reservoir rocks. Results showed relatively uniform 87Sr/86Sr values in hotspring deposits within each system, but occasional 87Sr/86Sr contamination induced by exogenous detritus input was also observed. The amount of detritus input relates to the potential for interaction with surrounding soils/rocks and is thus environmentally controlled. Hot-spring deposits with high Sr concentrations showed greater 87Sr/86Sr contamination resistance than those with low Sr concentrations, revealing the influence of Sr concentration in hot-spring deposits on detrital 87Sr/86Sr contamination. The detritus input also influenced the REE + Y signatures of the hot-spring deposits, underscoring the necessity of contamination assessment before geochemical interpretation. Excluding samples with significant 87Sr/86Sr and/or REE + Y contamination, the remaining samples closely mirrored their respective reservoir rocks in terms of 87Sr/86Sr, with partial overlap in REE + Y signatures. This suggests that the 87Sr/86Sr and REE + Y characteristics of hot-spring deposits provide valuable insights into reservoir rock types. However, variations in 87Sr/86Sr or REE + Y compositions between some hot-spring deposits and corresponding reservoir rocks indicate additional influencing factors beyond reservoir rock types. Therefore, a comprehensive understanding of reservoir rock types requires integrated geochemical characterization, probably including 87Sr/86Sr, REE + Y, and other parameters. These findings underscore the potential of geochemical characterization of hot-spring deposits for identifying geothermal reservoir rock types, and this geochemical approach can complement geological and geophysical data to improve exploration efficiency, especially in blind geothermal systems. [ABSTRACT FROM AUTHOR]

As a robust accessory mineral in igneous rocks, the mineralogical and geochemical characteristics of zircon can record the lithological differentiation and magmatic-hydrothermal evolution of highly evolved granitic systems. The F-Rb-rich, highly evolved Baishitouquan pluton of NW China exhibits gradual lithological changes from leucogranite, amazonite-bearing granite, and amazonite granite in the lower levels of the pluton to topaz-bearing amazonite granite, topaz albite granite, and pegmatite in the upper levels. In this study, three types of zircon grains were identified in five lithological zones based on textural and chemical characteristics. Type I zircon, which mostly occurs in leucogranite and amazonite-bearing granite, exhibits oscillatory zoning in cathodoluminescence images and experienced low degrees of radiation damage (0.21-0.68 × 1015 a-decay events/mg), which is indicative of its magmatic origin. Type II zircon, which mostly occurs in amazonite granite and amazonite pegmatite, exhibits textures that are indicative of hydrothermal alteration (e.g., spongy texture, porosity, and microcracks), and has elevated concentrations of some cations, such as Ca and Al. Type II zircon contains a higher concentration of non-formula elements, including rare earth elements (REEs), and Hf, Th, and U, than Type I and III zircons. Additionally, Type II zircon exhibits a significant M-type lanthanide tetrad effect and experienced varying levels of radiation damage (3.75-11.72 × 1015 a-decay events/mg). These characteristics suggest that Type II zircon has a hydrothermally altered origin. Type III zircon, which is restricted to the topaz-albite granite, has the smallest crystal size among all types of zircon grains, shows a euhedral to anhedral mottled appearance, and is characterized by patchy, cloudy, or irregular zoning, with numerous fluid inclusions. This type of zircon contains higher concentrations of Ti (110-1030 µg/g) than other types of zircon grains. Additionally, this type of zircon experienced limited radiation damage (2.18-3.69 × 1015 a-decay events/mg), and has a smooth surface and homogeneous internal textures. These characteristics suggest that Type III zircon is the product of fluid interaction with hydrothermally altered Type II zircon. Accordingly, this type of zircon crystallized directly from a Zr-saturated hydrothermal fluid during the later stages of magmatic-hydrothermal evolution. These contrasting textural and compositional features of the three types of zircon grains are indicative of three stages of magmatic-hydrothermal evolution of the Baishitouquan pluton: magmatic, magmatic-hydrothermal transition, and hydrothermal. These magmatic and hydrothermal processes were involved in the enrichment, transport, and precipitation of rare metals, such as Rb. Accordingly, this contribution demonstrates that the textures and chemistry of zircon grains can serve as petrogenetic indicators for assessing magmatic-hydrothermal evolution and rare-metal mineralization in highly evolved granitic systems. Furthermore, this study presents a model of the magmatic-hydrothermal evolution of F-rich, highly evolved granitic systems through the lens of zircon. [ABSTRACT FROM AUTHOR]

We report an integrated comprehensive dataset composed of petrography, pressuretemperature (P-T) calculations, monazite U-Th-Pb ages, and trace-element data from pelitic schists in the eastern Indus-Yarlung suture zone in the Milin area of the eastern Himalaya. These rocks represent the exposure of subduction-related rocks within the eastern Indus-Yarlung suture zone accretionary complex. The dominant mineral assemblages of the pelitic schists are garnet + kyanite + staurolite + biotite + quartz and garnet + kyanite + staurolite + biotite + paragonite + sillimanite with quartz, plagioclase, and ilmenite assemblages. Phase equilibrium modeling of sillimanite-bearing pelitic schists yielded peak P-T conditions of ~670-680 °C at ~8.6 kbar, similar to that of kyanite-bearing schists (~670 °C, ~8.8 kbar). Monazite grains with complex internal structures retained variable ages ranging from 28 Ma to 15 Ma, which correlate systematically with changes in the concentrations of Y, Th, U, and heavy rare earth elements and ratios of Th/U. Combined with petrologic analysis, we conclude that the pelitic schists experienced a long-lived prograde metamorphism from ca. 28 Ma to ca. 22 Ma. Peak metamorphism occurred in the period 22-21 Ma, followed by quasi-isothermal decompression until 15 Ma. The discrepancies among metamorphic P-T-t paths in the eastern Indus-Yarlung suture zone indicate the presence of not only collision-related regional metamorphism at medium P-T conditions, but also subduction-related high-pressure-low-temperature terranes in the Milin region. These two domains experienced different P-T evolution and tectonic histories and were juxtaposed in the early Neogene during the India-Asia continental collision. [ABSTRACT FROM AUTHOR]

Azurite, a historical blue mineral pigment, has previously been described to contain certain elemental impurities. These may originate from host rocks, vein fillings, or the primary copper ore mineralization. In this study, azurites (and also green malachites) from three important Central European deposits with a potential of being exploited for pigment usage already in the Middle Ages have been studied, together with azurite from Chessy, France, with a different geological setting. Using electron probe microanalysis and, more importantly, laser ablation inductively coupled plasma mass spectroscopy for trace elemental analysis, several indicators were pinpointed as important for provenance: characteristic elemental fingerprint of the deposit, e.g., elevated lead (Pb) in combination with rare earth elements, may be combined with zinc (Zn)/arsenic (As) ratio (indicating sources of excess Zn in the primary deposit) and the overall amount of metal impurities (suggesting the source mineral of copper for azurite formation). In addition, malachites from the same deposits were found to preferentially incorporate primary ore metal elements as well as Cd, Mg, Mn, or U. Therefore, if azurite pigment contains an elevated amount of malachite as an impurity, it may significantly influence the overall elemental composition. The results obtained on geological samples were applied to two micro-samples of works of art containing azurite-rich layers originating from the 13th–14th and 16th centuries. It was shown that it is highly beneficial to focus on the overall trace elemental composition of the paint layer and not on the admixed mineral grains, as their presence, especially in minute micro-samples, is largely accidental and thus not representative. Although a higher number of samples need to be studied in the future, the newly described criteria made it possible to exclude some of the localities of the employed azurite pigment. This confirmed the key importance of trace elements analysis of mineral pigments for the provenance studies of fine arts. [ABSTRACT FROM AUTHOR]

Utilization of actinides and rare earth elements is only possible by separating these metals with high purity. The materials used in separation must have thermal, chemical, mechanical, and radiation resistance. In the present study, separation experiments of actinides and rare earth elements (REEs) were carried out using purified H2SO4 leach liquor. Polyacrylonitrile (PAN)-supported Ti, Zr, and Si oxide nanocomposites were tested for the selective separation of Th, U, Gd, Eu, Sm, Pr, Nd, La, Ce, and Y. The effects of pH, contact time, adsorbent/solution ratio, and temperature on distribution coefficient (KD) and adsorption capacity (Q) were investigated. The synthesized nanocomposites tend to separate the elements into two main groups: Th, U, Gd, Eu and Sm, Pr, Nd, La, Ce. Notably, it was observed that the separation of Th and U from the remaining elements is promising at 15 °C. Additionally, the separation can be further improved depending on the differences in desorption efficiency. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are essential for high-tech and low-carbon economies. Achieving global net-zero emissions by 2050 would require a significant increase in mineral input, including 3–7 times more REEs. At present, there are no direct high-grade ores of heavy REs like terbium. Bastnasite, monazite, and xenotime are the primary sources of terbium, while southern Chinese ion-adsorption clays are the richest commercial sources. To address the scarcity of rare earth resources, countries lacking RE deposits should focus on developing innovative and economically viable recycling techniques for the recovery of REs like terbium from different secondary resources. Spent fluorescent lamp phosphor powder represents a potential secondary resource for terbium recovery, although research efforts have been focused mostly on other REEs than Tb as value-added products. Hydrometallurgical processing is widely employed to extract terbium from different resources. The present review systematically summarizes in detail the major recovery/separation techniques used and critically evaluates the potential of terbium recovery from mineral resources and end-of-life fluorescent phosphor wastes. The advantages and limitations of each of these technologies have been provided. The objective is to foster valuable insights for researchers and the development of economical and promising extraction technologies for the recovery of terbium. [ABSTRACT FROM AUTHOR]

Natural minerals as catalysts have the advantages of wide source and environmental friendliness. However, it is still challenging to develop mineral-based NH3-SCR catalysts with high NO conversion and N2 selectivity at low temperatures. Therefore, we use magnetic separation rare earth tailings with certain catalytic activity and acidic sites as the carrier, and introduce metal elements Mo and Ce with different valence states as active components to stimulate the catalytic activity of magnetic separation rare earth tailings by multi-element co-doping. The catalysts were tested and analyzed by XRD, XPS, BET, NH3-TPD and other characterization methods. The results show that there is an electronic interaction between Fe, Mo and Ce on the surface of Mo-Ce/magnetic rare earth tailings catalyst. The increase of Fe3+, Mo5+ and Ce3+ promotes the adsorption of NH3 and NO on the surface of the catalyst. With the introduction of Ce, the redox capacity and Brønsted acid strength of the catalyst at low temperature are significantly enhanced, thus accelerating the SCR reaction. The results of this study not only provide a theoretical basis for the high-value utilization of magnetic separation rare earth tailings, but also expand the raw material range of NH3-SCR denitration catalyst. [ABSTRACT FROM AUTHOR]

Samples of siliceous rocks of the Southern Kambalny Central Thermal Field (SKC) containing a unique ore mineralization were studied. Optical microscopy, scanning electron microscopy, X-ray microanalysis, X-ray diffraction, ICP-MS, and Raman spectroscopy were used in this study. High concentrations and a wide range of rare and rare-earth elements were found in siliceous rocks. Silicates (quartz, moganite, and opal-crystobalite/tridymite opal), oxides (hematite and anatase), hydroxides (goethite), carbonates (calcite with Fe and Mn impurities), sulfates (barite with Sr impurity and gypsum), sulfides (pyrite, marcasite, chalcopyrite, and chalcocite), phosphates (xenotime-Y, YPO4 with impurities of lanthanides, S, Ca, and As; berlinite, AlPO4 with the V impurity), and apatite were identified. Structures of anatase replacement by quartz often in association with pyrite were identified. The mineralization of SKC siliceous rocks reflects the physicochemical specificity of deep metal-bearing solutions. [ABSTRACT FROM AUTHOR]

The present research utilizes the simple "plug-and-play" strategy to effectively impart layered rare-earth hydroxides with remarkable sensitivity, selectivity, and rapid fluorescence sensing detection ability towards nitroaromatic compounds, employing the excited-state proton transfer fluorescence quenching mechanism. This opens new possibilities for the efficient and accurate detection of toxic and hazardous nitroaromatic compounds and effectively protecting environmental health and public safety. [Display omitted] Convenient, rapid, and accurate detection of nitroaromatic organic toxins and harmful substances is of great significance in research. In the present study, two-dimensional layered rare-earth hydroxides (LYH) were used as ion-exchange matrix materials, and the anionic fluorescent dye molecules (HPTS) were successfully introduced into the LYH structures in situ via a simple and effective "plug-and-play" strategy, which gave the compounds ultra-sensitive fluorescence sensing detection of nitrobenzene, p-nitrotoluene and p-nitrophenol (Fluorescence response time < 1 sec , and the LOD for nitrobenzene, p-nitrophenol and p-nitrotoluene reached an impressive 349 ppb, 22 ppb and 98 ppb, respectively). Combined with theoretical calculations, we elucidated in detail the fluorescence quenching response mechanism of the LYH-HPTS towards nitroaromatic. Additionally, we also constructed fluorescent paper sensor, which effectively transformed the LYH-HPTS from theoretical detection to device application. The LYH-HPTS material is not only simple to synthesize, cost-effective and stable, but also has the features of fast response, excellent sensitivity and selectivity, and good reproducibility, which provides a new approach for the rapid and accurate detection of nitroaromatic. [ABSTRACT FROM AUTHOR]

Desalination brine can negatively impact the marine environment in several ways, although there are ongoing discussions regarding the severity and magnitude of environmental effects. A fascinating strategy to lessen any adverse effects is to undertake resource recovery from the brine, which also has the potential for additional revenue generation. More recently, the increasing demand for secure and less geographically restricted sources of precious or rare earth minerals, integrated with growing awareness of waste management and environmental sustainability, is driving the development of economically viable technologies to recover valuable materials from waste streams. This article provides an overview of different methods and technologies, including reverse osmosis (RO), electrodialysis (ED), and distillation, that can be used to recover precious materials, including Li, Mg, Na, and Rb and valuable blends from various waste sources and thus create a more sustainable and circular economy. The mechanisms are discussed in detail, including electrochemical processes (electrolysis, ED, and capacitive deionization), thermal desalination (multistage flash distillation and membrane distillation), pressure‐driven desalination (RO and nanofiltration), and microbial desalination cells. Challenges associated with recovering precious materials from waste streams, such as fouling, scaling, and environmental impact, along with further research directions and potential applications of desalination technologies, are also addressed. [ABSTRACT FROM AUTHOR]

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The study aims to synthesize nano CeO2 and Pr2O3 materials to use as fertilizer for cultivation of the Salvia miltiorrhiza Bunge, which is also known as Danshen, an important medicinal plant in many Asian countries. The extraction experiments were also conducted to determine tanshinone IIA contents in the Danshen root to acutely explore effects of the nano‐materials on accumulation of valuable medicine in the plant. The obtained results indicated that nano CeO2 and Pr2O3 applications significantly induced both growth and tanshinone IIA contents of the Danshen. Firstly, the CeO2 application greatly induced side branch and root development of the Danshen rather than the height of the plant, while the Pr2O3 application greatly induced plant height and root growth of the Danshen rather than side branch development. In comparison, the CeO2 effectively induced root growth and tanshinone IIA content in the Danshen rather than the Pr2O3 did. Finally, simultaneous applications of nano Pr2O3 and CeO2 revealed synergic effects to greatly promote the growth of the Danshen. The tanshinone IIA content extracted from the roots of the mixture Pr2O3 and CeO2 exposed Danshen was approximately 0.4318 %, which was higher than those of single CeO2 and Pr2O3 exposed plants. [ABSTRACT FROM AUTHOR]

The social risks of green energy transition are underexplored. One of the important questions is which materials used in green energy technologies offer the greatest social benefits, such as ensuring decent living conditions, and which pose the most social risks. To address this issue, we develop a dynamic material-energy flow model integrating system dynamics, social life cycle assessment, and geometallurgical approaches. The analysis focuses on critical materials: Rare Earth Elements, Nickel, Silicon, Graphite, Magnesium, Gallium, Germanium, Indium, Aluminum, Cobalt, Lithium, Zinc, and Tellurium used in wind turbines, electric vehicles, lithium-ion batteries and solar photovoltaic panels. We assess their social impact on work safety, gender equality, informal employment, labor income share, employment rate, and child labor—key issues addressed by Sustainable Development Goals 1, 5, and 8. Here we show that Aluminum production for electric vehicles, wind turbines and solar photovoltaic panels generates the most jobs and income opportunities, while extraction of Cobalt, Lithium, Silicon, and Zinc carry the highest social risks. This study identifies materials used in green energy technologies with the most social benefits and risks. Aluminum production creates the most jobs while cobalt, lithium, silicon and zinc pose the highest risks including child labor and unsafe work conditions. [ABSTRACT FROM AUTHOR]

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution – transmittance electron microscopy (HR-TEM), field emission–electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV–visible diffusive reflectance spectroscopy (UV–Vis-DRS) studies revealed a band gap energy of 3.18 eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10 ppm. The remarkable photocatalytic performance was achieved within 60 min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation. [ABSTRACT FROM AUTHOR]

Rare-earth magnesium alloys exhibit higher comprehensive mechanical properties compared to other series of magnesium alloys, effectively expanding their applications in aerospace, weapons, and other fields. In this work, the tensile strength, yield strength, and elongation of a Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy under different process conditions were determined, and a large number of microstructure observations and analyses were carried out for the tensile specimens; a prediction model of the corresponding mechanical properties was established by using a convolutional neural network (CNN), in which the metallographic diagram of the rare-earth magnesium alloy was taken as the input, and the corresponding tensile strength, yield strength, elongation, and three mechanical properties were taken as the output. The stochastic gradient descent (SGD) algorithm was used for parameter optimization and experimental validation, and the results showed that the average relative errors of the tensile strength and yield strength prediction results were 1.90% and 3.14%, respectively, which were smaller than the expected error of 5%. [ABSTRACT FROM AUTHOR]

The electrospun light rare earth orthochromites RCrO3 (R = La, Pr, Nd, Sm, Eu) nanofibers have perovskite-type orthorhombic structures. Raman spectra proved the typical vibration modes of the rotation, bending, and stretching of the CrO6 octahedra in RCrO3 nanofibers. The rare earth element with large ion radius, low electronegativity, and remarkable affinity for oxygen, and the rich redox reaction of Cr endow RCrO3 a potential energy storage material for supercapacitors. It is highly significant to investigate the electrochemical properties of RCrO3. The electrochemical properties of the RCrO3 nanofibers as supercapacitor electrodes were elucidated. At 0.5 A/g, the LaCrO3, PrCrO3, NdCrO3, SmCrO3, and EuCrO3 nanofibers exhibited the specific capacitance values of 267.8, 132.8, 157.6, 170.5, and 170.4 F/g, respectively. First-principles density functional theory method was used to clarify the electronic structure and total density of states of the RCrO3 nanofibers. This study provides a rational design and fabrication method to pseudocapacitor electrodes. [ABSTRACT FROM AUTHOR]

Samarium oxide (Sm 2 O 3), a quintessential lanthanide oxide, garners significant attention in electrocatalysis and photocatalysis. However, the physicochemical properties of precursors and rare earth oxides are hampered by traditional precipitation reactions, mainly due to the asymmetry of time and space. A new anti-clogging strategy based on pneumatic impingement flow is proposed. Subsequently, nano-sized Sm 2 O 3 powder with an ellipsoidal morphology and a median particle size of 70 nm are prepared using the integration of microchannel reaction and microwave heating. Correlation analysis and morphology evolution mechanism reveal intricate relationships among different variables, emphasizing the importance of achieving balance to effectively control crystal properties. Numerical simulations show that the selective heating of microwave make it significantly superior to conventional. Preliminary economic analysis suggests that producing 1 kg of nano-Sm 2 O 3 can yield $57.56. The combination of microchannels and microwaves offers a pathway for the high-value utilization of rare earths and holds significant industrial application prospects. [ABSTRACT FROM AUTHOR]

In order to improve the comprehensive performance of thermosetting phthalonitrile resin (PN) composites, a novel molten hybrid (Nd2O3@DM35) was successfully prepared by loading Neodymium Oxide (Nd2O3) on the surface of low melt‐point molten oxide (DM35). In thermal gravimetric analysis, the addition of 30 wt% Nd2O3@DM35 postponed the temperature of 5% mass loss (T5%) of PN hybrid (PN‐NdD30) from 485 to 521°C. A series of thermal aging experiments were designed to prove the thermal stability of modified PN. The surface morphology of PN‐NdD30 was mostly maintained after thermal aging. Compared with pure PN, the flexural strength (FS) and interlaminar shear strength (ILSS) of PN‐NdD30 composites at room temperature increased by 31.4% and 32.8%, respectively. After aging at 400°C for 20 min, the FS and ILSS retention rates of PN‐NdD30 composites were 78.4% and 91.5%, respectively. In this work, the introduction of novel hybrid improved the thermal stability of PN composites, while enhancing their mechanical properties at different temperatures. Based on all the results, the heat resistance and mechanical mechanism of PN‐NdD30 composites were carefully analyzed. Highlights: A molten hybrid was prepared by Nd2O3 and low melt‐point molten oxide.The novel hybrid can form a continuous protective layer at high temperatures.In the aging test, the mass loss of PN‐NdD30 was significantly reduced.Mechanical properties of PN composites at different temperatures were improved.A novel molten concept was introduced in the heat resistance modification of PN. [ABSTRACT FROM AUTHOR]

Ruthenium-based nanomaterials are considered to be promising electrocatalysts for HER due to their higher activity. However, the active site exposure is low, and the catalytic mass activity is low. In order to achieve the particular aims, several types of engineering, such as crystal engineering, topography engineering, heterostructures and support engineering, have been used to catalysts. Here we report RuO 2 supported on CeO 2 -NC, owing to the abundant heterostructures and the presence of oxygen vacancies, the RuO 2 /CeO 2 -NC catalyst showed outstanding HER performance (98.2 mV, 53 mV and 298 mV@100 mA cm−2 in acidic, alkaline and neutral, respectively). Moreover, RuO 2 /CeO 2 -NC also has an excellent electrocatalytic durability for 40 h. The experimental achievements show that oxygen vacancies and heterostructures could jointly enhance performance of catalyst HER. • CN-loaded CeO 2 composite RuO 2 structure. • We present a functionalization by arming RuO 2 nanoparticles with CeO 2 -NC enriched with oxygen vacancy, which can activate the superior HER catalytic activety. • The charge transport at the heterogeneous interface present in RuO 2 /CeO 2 -NC effectively enhances the reaction kinetics during electrocatalysis. • RuO 2 /CeO 2 -NC exhibits high activity and durability for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

The Kerguelen Plateau is the second biggest submarine large igneous province (LIP) on Earth, however, the nature of the lithospheric mantle source underlying it remains poorly constrained. In this contribution, we provide novel insights into the oceanic lithospheric mantle underlying Heard Island (southern Indian Ocean), which represents the most recent and active phase of volcanic activity (<1 Ma) in the Kerguelen Plateau. We present petrographic and geochemical data for a suite of spinel-bearing harzburgite xenoliths hosted in basanite lavas and provide detailed constraints for distinguishing in situ mantle metasomatism from post-entrapment modification of the xenoliths following interaction with the host magma. We demonstrate that the xenolith mineral compositions and textures preserve a complex multistage history of different modal and cryptic transformations that occurred in the mantle due to: i) high degrees of partial melting that produced highly refractory whole-rock Mg# (Mg# = (Mg + Fe)/Mg × 100; 88–92), major element (FeO/MgO = 0.17) and mineral compositions (e.g. highly forsteritic olivine; Fo = (Mg + Fe)/Mg × 100; 91–92 mol %); ii) solid-state re-equilibration reactions during decompression that caused exsolution of clinopyroxene and Cr-spinel from xenolith orthopyroxene to form symplectite intergrowths; iii) cryptic metasomatism affecting the composition of xenolith clinopyroxene (i.e. enrichment in Na, Th, U and light rare earth elements, and depletion in Rb, Nb, Zr, Hf and Ti) due to interaction with carbonatitic melts in the mantle. Mantle fragments, entrapped by ascending basanite magmas as xenoliths were further modified by reactions with the host magma. This resulted in the partial dissolution of mantle orthopyroxene and replacement by newly formed and compositionally distinct assemblages of clinopyroxene (Mg# 87–91), olivine (Fo: 81–88 mol %) and Cr-spinel (i.e. 'wehrlitisation' of the xenoliths). This study highlights the utility of combining petrography and mineral chemistry to decipher the complex and sometimes overprinting and masking effects that different processes (e.g. melting events, metasomatism) exert on the lithospheric mantle, as well as constrain the processes that modify the xenoliths during transport towards the surface. [ABSTRACT FROM AUTHOR]

The extraction of rare earth elements (REEs) from mineral resources is of significant global importance due to their critical role in modern technologies. This study focuses on the leaching behavior of artificial cerium and lanthanum phosphates using nitric, sulfuric, and hydrochloric acids under varying conditions of acid concentration and temperature. Our experiments demonstrated that the maximum extraction efficiency of lanthanum and cerium was achieved with nitric acid solutions at concentrations of 12.5 mol/dm3, with 85.0% and 79.1% extraction efficiency, respectively. The leaching mechanism involved the protonation of phosphate anions, which disrupted the phosphate matrix, facilitating the dissolution of lanthanum and cerium into solution. Sulfuric acid, although less effective at room temperature, proved to be the most thermodynamically favorable leaching agent at higher temperatures due to the formation of stable sulfate complexes. Additionally, hydrochloric acid displayed high selectivity for cerium extraction, although its applicability is limited by complexation and environmental concerns. This study offers new insights into optimizing REE recovery from phosphates, demonstrating the advantages of sulfuric acid for industrial-scale leaching processes due to its economic and thermodynamic benefits. The novelty of this work lies in its systematic comparison of the three acids' effects on REE extraction, providing a comprehensive framework for selecting optimal leaching agents based on specific operational conditions. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) hold significant industrial, scientific, and modern technological worth. This study focused on detecting and quantifying REEs in various geological ore samples. These samples were collected from different REE-bearing locations recommended by geological experts. The analysis was conducted using laser-induced breakdown spectroscopy (LIBS) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). In this work, LIBS methodology was employed using three different configurations: standard LIBS, LIBS with an applied magnetic field, and LIBS with both an applied magnetic field and target sample heating within an optimal temperature range. Elements from the REE group, specifically lanthanum (La), cerium (Ce), and neodymium (Nd), were identified and quantified. To detect, quantify, and validate the results from LIBS and LA-TOF-MS, we utilized an array of analytical techniques—Energy-Dispersive X-ray Spectroscopy (EDX), Energy-Dispersive X-ray Fluorescence Spectrometer (ED-XRF), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Interestingly, the quantitative results for REEs (La, Ce, and Nd) in the ore samples obtained using the LIBS technique with various configurations were found to be in agreement with those from LA-TOF-MS, EDX, XRF, and ICP-OES. In addition, LIBS enables detailed microchemical imaging, allowing the map of the spatial distribution of elements within the mineral–ore matrix. The high-resolution microscale elemental mapping of REEs was accomplished using the emission lines Ce (II) at 446.0 nm, La (II) at 492.1 nm, and Nd (II) at 388.8 nm. By integrating multiple analytical techniques, our study enabled the construction of a complete elemental distribution map, providing new insights into the geochemical processes and mineral composition of rare earth ores, while advancing geochemistry and contributing valuable data for rare earth resource exploration. [ABSTRACT FROM AUTHOR]

Yongxin Gold Deposit is located in the southern part of Duobaoshan Cu-Mo-Au metallogenic belt. To understand the genesis of the deposit and provide exploration insights, a study was conducted on the rare earth elements, micro-elements, and isotopic composition of gold-bearing pyrite. The results indicate that the chemical composition of pyrite shows enrichment in light REEs and depletion in heavy REEs, with a right-sloping REE distribution pattern. The pyrite is enriched in high-field-strength elements such as U, Th, Zr, and Hf, and depleted in large-ion lithophile elements like Ba and Sr. Ratios such as w(Hf)/w(Sm), w(Nb)/w(La), and w(Th)/w(La) suggest that the ore-forming fluid contained more Cl than F. A negative Eu anomaly and the absence of a Ce anomaly indicate that the ore-forming fluid formed under reducing conditions. Ratios like w(Y)/w(Ho), w(Zr)/w(Hf), and w(Nb)/w(Ta) suggest that the mineralization process did not involve external hydrothermal fluids, nor did metasomatism occur, with the ore-forming fluid closely related to both mantle and crustal sources. The sulfur isotopic characteristics indicate that the ore-forming materials originated from deeper sources. Genetic indicators such as w(Co)/w(Ni) and w(Fe)/w(S＋As) suggest that the deposit is of a meso-epithermal volcanic hydrothermal origin. Based on the magmatic origin, tectonic setting, diagenesis-mineralization age, metallogenic process, geochemical characteristics, and the main features of representative gold deposits in the region, it is concluded that Yongxin Gold Deposit belongs to a porphyry metallogenic system, forming during the Early Cretaceous as a meso-epithermal, relatively Cl-rich, weakly reducing gold deposit. [ABSTRACT FROM AUTHOR]

We report the discovery of upper Paleozoic komatiites from a location near Mashhad in NE Iran. Like Archean komatiites, they erupted as differentiated lava flows with olivine spinifex-textured upper portions and olivine cumulate lower portions. They are associated with komatiitic basalts and undifferentiated ultramafic units and are intercalated with clastic and carbonate sedimentary rocks. Using the compositions of samples with randomly oriented spinifex and the forsterite contents of olivine, we estimate that the parental magmas contained >20 wt% MgO. As such, they represent only the second known occurrence of post-Archean komatiite. Their geochemical compositions show relatively low Al/Ti and depleted heavy rare earth elements, indicating that they belong to the Al-depleted variety. This is the only reported post-Archean example of this type of komatiite. The parental magmas probably formed by moderate degrees of melting (~20%) of a hydrous peridotite source at a depth of ~180 km and erupted into a subduction zone at the margin of the Paleo-Tethys Ocean. [ABSTRACT FROM AUTHOR]