Search Results (312)

The electrochemical regeneration of sodium borohydride (NaBH₄) from spent metaborate is a central bottleneck for circular hydrogen storage. (1) Background: The eight-electron reduction of the aqueous borate species B(OH)₄⁻ to BH₄⁻ is thermodynamically out-competed by the hydrogen-evolution reaction (HER) by about 0.41 V at every pH, so selectivity can only be won kinetically. (2) Methods: We advance an ambiphilic-site hypothesis, screen 30 candidate metal centres using entirely experimental, tabulated descriptors (bulk HER exchange current density; gas-phase M-O bond energy) with no new electronic-structure computation, and then audit the transferability of both descriptor axes against published, corrected DFT datasets for nitrogen-coordinated single-atom sites. (3) Results: At the parent-metal level, the two axes are orthogonal (Spearman ρ = 0.02) and the score passes a family-level experimental validation over seven bulk-electrode metals (ρ = 0.69; exact permutation p = 0.050), separating the HER-dominated noble-metal family from the single-atom Mn benchmark. The site-level audit shows that the oxophilicity axis transfers to M-N₄ sites almost quantitatively (ρ = −0.84 pyridine-4N, −0.95 pyrrole-4N, n = 23) while the bulk HER axis does not, and that site-level scaling between oxygen and hydrogen binding narrows the productive window to oxophilic centres that over-bind hydrogen. (4) Conclusions: The site-anchored screen redirects the search from the parent-metal leaders (La, Ce, Y, Ti, Sc) to refractory single-atom centres, with W, Nb and Mo as priority synthesis targets (Re excluded on scarcity; Zr, Hf, Ta as data-supported extensions; Ti as the sustainability-anchored borderline case) and the lanthanides retained only as explicitly extrapolative candidates. All data and analysis code are openly deposited. Full article

A series of novel heterometallic rare-earth chloroterephthalate metal–organic frameworks with the general formula (Tb_xGd_1−x)₂(Cl-1,4-bdc)₃·5H₂O (x = 0–1) were synthesized via direct precipitation from aqueous solutions. The structural and photophysical properties of these compounds were studied in detail. All compounds exhibit bright luminescence upon UV excitation into the ligand absorption band due to an efficient antenna effect. The photoluminescence quantum yield shows a non-monotonic dependence on the concentration of the terbium ion with a maximum value of 71% achieved for the compound containing equal molar fractions of the lanthanide ions. The (Tb_0.5Gd_0.5)₂(Cl-1,4-bdc)₃·5H₂O sample was evaluatedfor its utility in both qualitative and quantitative analysis of selected metal ions and in latent fingerprint development. It was shown to enable the detection of Cr(III), Fe(III), and Cu(II) ions through luminescence quenching, with the emission intensity being concentration-dependent. This behaviour highlights the compound’s potential as a basis for analytical protocols and materials aimed at the quantitative determination of these metal ions. Full article

Hospital wastewater has begun to act as an important source of emerging contaminants, including rare earth elements (REEs), mostly lanthanides, and radiopharmaceutical residues originating from diagnostic and therapeutic nuclear medicine procedures. The increasing use of gadolinium-based contrast agents, lutetium-containing therapeutics, technetium-99m tracers, iodine-131, yttrium-90, and gallium-68 radiopharmaceuticals has raised growing concerns regarding the release of radioactive and metal-containing compounds into aquatic environments. Conventional wastewater treatment plants are often inefficient in removing these contaminants because of their high chemical stability, low environmental concentrations, and complex aqueous speciation. In this context, hybrid nanomaterials containing silver nanoparticles (AgNPs) have attracted increasing interest for both monitoring and remediation applications. AgNP-based systems exhibit unique plasmonic, catalytic, antimicrobial, and sensing properties that can be exploited in adsorption, photocatalysis, membrane filtration, electrochemical detection, and surface-enhanced Raman spectroscopy (SERS). This review critically analyzes recent advances in hospital wastewater treatment and how hybrid nanomaterials containing silver nanoparticles (AgNPs) are emerging. The review places a particular focus on contamination by REEs and radiopharmaceuticals residues, which to date, as far as we know, remains a challenging and understudied aspect, as reflected by limited publications. Full article

In this study, taking NdCl₃ and 2-amino-1,4-benzenedicarboxylic acid (H₂ATA) as raw materials, a novel lanthanide metal–organic framework, Nd(ATA), was synthesized by the coprecipitation method. After loading antibiotic levofloxacin (LEV), Nd(ATA) was combined with GelMA hydrogel to prepare a drug-loaded composite hydrogel, LEV@Nd(ATA)-Gel, which can emit near-infrared fluorescence under excitation at 808 nm and possesses improved mechanical properties compared to pure GelMA hydrogel. LEV@Nd(ATA)-Gel exhibited high bactericidal activity and low cytotoxicity, with cell viability increased by 35% compared to the control group. The release rate of the loaded LEV was found increasing with the pH decreasing from 7 to 3, and demonstrated a potential responsiveness to wound microenvironment. Furthermore, drug delivery studies revealed a significant correlation with the fluorescence intensity of the composite hydrogel and the drug release behavior, and the extent of drug release was quantitatively captured by an in vitro imaging technology. This study successfully integrated the drug release with fluorescent signal of carrier, providing a highly sensitive and visualizable strategy for the development of internal wound adhesive. Full article

The structural, electronic, and magnetic properties of the PdRSb, usually also referred to as RPdSb, ($R=$ La-Lu) semi-Heusler compound series have been systematically investigated using first-principles calculations based on Density Functional Theory (DFT). Our structural optimizations reveal that the cubic $C{1}_{\mathrm{b}}$ A-type variant is the energetically most favorable and thermodynamically stable ground state across the entire series. The calculated equilibrium lattice constants follow the well-known lanthanide contraction trend, with the exception of the Yb-based compound, which displays an anomalous lattice expansion. Magnetic stability analysis demonstrates that the magnetism is highly localized at the rare-earth (R) sites and closely follows the progressive filling of the $4f$ shell, peaking at $7{\mathsf{\mu }}_{\mathrm{B}}$ for PdGdSb, while PdLaSb, PdYbSb, and PdLuSb remain non-magnetic. Furthermore, our electronic structure calculations reveal a rich variety of behaviors: PdLaSb and PdLuSb behave as gapless semiconductors, while most of the magnetic compounds exhibit near half-metallic characteristics. Notably, PdCeSb is predicted to be a perfect half-metal with an integer magnetic moment of $1{\mathsf{\mu }}_{\mathrm{B}}$. These findings highlight the significant chemical tunability of the PdRSb family, positioning them as promising candidates for future applications in spintronics and magnetoelectronics. Full article

The development of highly sensitive luminescence sensing materials has attracted much attention in recent years. In this study, a new two-dimensional porous europium metal–organic framework (EuMOF, [Eu(DHDA)₁.₅·3H₂O]_n; DHDA = 2,2-dihydroxyacetic acid) is obtained, characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), luminescence, and Fourier transform infrared spectroscopy (FT-IR). At the best excitation at 295 nm, EuMOF shows red luminescence (CIE: 0.6255, 0.3740) and has four obvious peaks at 582, 605, 641, and 689 nm, which are due to ⁵D₀ → ⁷F₁, ⁵D₀ → ⁷F₂, ⁵D₀ → ⁷F₃, and ⁵D₀ → ⁷F₄ transitions, respectively. Studies have shown that EuMOF is a stable, fast-responding, and highly sensitive luminescence sensor for isoprocarb and levofloxacin (Lvx) in aqueous solutions, apple peel and rice extract solutions, and real urine, which are closely associated with food safety and human health. The sensing behavior toward isoprocarb and Lvx may be attributed to the specific binding of the two analytes to EuMOF. The sensing of isoprocarb is a dynamic luminescence-quenching process, while that of Lvx is a dynamic luminescence-enhancing process. The limits of detection (LOD) for isoprocarb and Lvx are as low as 1.0 and 0.5 nM, respectively, which are much lower than the Chinese national standard (GB 28260-2011, 2.583 μM). EuMOF also demonstrates strong anti-interference detection of isoprocarb in apple peel and rice extract solutions, as well as Lvx in real urine, with excellent detection stability in a 0.01~9.0 nM range. The recovery rates for isoprocarb and Lvx in real samples are 99.12%~101.25%. This work provides the first bifunctional lanthanide sensor for pesticides and antibiotics. Full article

The growing field of nanobiotechnology could provide an alternative platform for the development of new therapeutic agents. A potential means for achieving these goals are nanoparticles of rare-earth metals, for example, nanoceria. According to the results of numerous in vitro and in vivo studies, not only oxide forms of lanthanides can demonstrate a pharmacological effect. A promising nano-object for biomedical application is cerium phosphate, which exhibits both properties characteristic of cerium dioxide and its own unique properties, due to the diversity of morphology. However, at present, a unified methodological approach has not been formulated that would make it possible to formulate principles for obtaining a compound with specified properties. This review was conducted on using the international databases PubMed, PubChem, Scopus and Google Scholar, and included original studies and reviews. The literature describes the preparation of cerium phosphate nanoparticles by the hydrothermal, chemical precipitation, microwave, and sol–gel methods. It was established that reaction temperature, pH value of the medium, use of organic solvents, ratio of reagents, and precursors have a direct influence on the size, shape, and structure of the obtained nano-object, making it possible to synthesize nanospheres, nanorods, and nanoneedles by regulating these parameters. In addition, the strategy of obtaining nano-objects with specified properties can be implemented by using excipients of predominantly polymer nature. The use of auxiliary substances is capable both of exerting a stabilizing effect and improving adherence to the nanoscale range, and of influencing pharmacological activity. The literature describes the possibility of using cerium phosphate as a redox-active, regenerative, antibacterial, sunscreen, and antitumor agent. However, the insufficient amount of data on the toxicological profile, as well as the results of in vivo studies, remains a significant limitation for the introduction of cerium phosphate into clinical practice. Thus, the purpose of the present review is to identify patterns that make it possible to formulate recommendations for the synthesis of cerium phosphate with specified properties, to assess factors affecting its suitability for use in biomedicine, and to consider its prospects and limitations. Full article

This work reports a novel dithiophosphinic acid extractant, bis(isobutylphenyl)dithiophosphinic acid (HL), for the mutual separation of Am(III) and Cm(III) and for the separation of trivalent actinides (An(III)) from lanthanides (Ln(III)). The compound was successfully synthesized and structurally confirmed by ¹H and ³¹P NMR spectroscopy. Focusing specifically on Am(III) and Cm(III), the extraction behavior was systematically investigated as a function of pH, ligand concentration, nitrate concentration, and temperature. Compared with the conventional extractant, bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HL₃₀₁), HL exhibits stronger extraction efficiency (pH_1/2 = 3.39 for Am(III) and 3.64 for Cm(III)) and a notably improved separation factor for Am(III) over Cm(III) (SF_{Am(III)/Cm(III)} = 4.8), while retaining excellent separation ability for An(III) from Ln(III). The extraction proceeds via a cation-exchange mechanism, yielding a 1:3 metal-extractant complex with the release of three protons. Increasing nitrate concentration suppresses extraction due to the competition for metal ion between NO₃⁻ in the aqueous phase and the extractant. The extraction reaction is endothermic with negative entropy changes, exhibiting ΔH° values of 24.06 kJ·mol⁻¹ for Am(III) and 27.12 kJ·mol⁻¹ for Cm(III) at 298.15 K, along with ΔS° values of −90.63 J·mol⁻¹·K⁻¹ and −89.11 J·mol⁻¹·K⁻¹, respectively. This work offers a promising extractant for the separation of Am(III) from Cm(III) and An(III) from Ln(III), and mechanistic insights into coordination–selectivity relationships involving soft sulfur donors. Full article

This article reviews the state of the art of laser ablation and deposition techniques applied so far to more than 50 elements, including metals, metalloids and lanthanides, yielding a wide variety of compounds in the form of thin films. Laser deposition processes have been performed in high-vacuum (HV) reactors at pressure values ranging between 10⁻¹ and 10⁻⁵ Pa, namely pulsed laser deposition (PLD), or, under different reactive gas ambient (O₂, N₂, CH₄, NH₃ and many others), so-called reactive pulsed laser deposition (RPLD), with the aim to form thin films with desirable chemical compositions. While a few metals have not been deposited as pure metallic films because they have no immediate technological interest, others, like alkali and alkaline earth metals, cannot be deposited in pure metallic form due to their very strong reactivity with oxygen, water vapor and hydrogen molecules which are always present, even in ultra-high-vacuum (UHV) systems, at pressure values of 10⁻⁵–10⁻¹⁰ Pa. Furthermore, elements of the Mendeleev periodic table with an atomic number higher than 88, such as actinides and synthetic elements, are dangerous to handle and deposit in the form of thin films due to their high radioactivity; therefore, they are excluded from this review. The inclusion of the non-metal thin films of carbon (C) and related chemical compounds prepared by PLD and RPLD in the present review is justified by the extensive research and the numerous scientific articles reported in the field. All the results obtained by PLD and RPLD techniques so far are discussed and presented in tabular format to guide the reader. Full article

Rare-earth elements (REEs), which include the entire lanthanide series together with scandium and yttrium, have unique electronic configurations and coordination chemical properties that provide them with special magnetic, optical, and redox abilities. Generally used for diagnostic imaging and theranostic applications, increasing evidence emphasizes their potential as direct anticancer agents. This review aims to present a thorough investigation of the studies published in the last ten years that focus on the intrinsic anticancer properties of REE-based molecular complexes and nanostructures, without discussing their recognized imaging functions. Rare-earth compounds exhibit selective cytotoxicity against malignant cells via mechanisms that mainly include modulations in the generation of reactive oxygen species, mitochondrial dysfunctions, interaction with DNA molecules, apoptosis, and ferroptosis induction, as well as radiosensitization. Molecular complexes that are based on the trivalent coordination chemistry of REEs enable them to target biomolecules like DNA and serum albumin. Nanostructured systems, on the other hand, render tumors more responsive to treatment by improving the cellular uptake, enabling surface functionalization, and controlling ROS generation. Terbium, thulium, yttrium, scandium, ytterbium, cerium, erbium, dysprosium, and europium show different levels of anticancer activity in both in vitro and in vivo cancer models. They often exert more toxicity in tumor cells than in normal tissues, thus exhibiting selective anticancer effects. The findings collectively underscore the therapeutic potential of REE-based compounds as novel metal-based anticancer agents and advocate for additional mechanistic and translational research to enhance their clinical applicability. Full article

The electrodeposition of rare earth metal alloys has attracted considerable interest, not only due to the challenges associated with the reduction in metal ions, but also because of their unique material properties and promising technological applications. This review presents a comprehensive analysis of the state-of-the-art in the electrochemical deposition of these alloys, focusing on various electrolytic systems, including aqueous solutions, organic molecular solvents, ionic liquids, and deep eutectic solvents. Despite inherent problematic factors such as low reduction potentials, competing hydrogen evolution reactions, and difficulties in controlling metal formation, recent advancements have enabled improved control over film formation, typically through the induced codeposition of lanthanides with iron-group metals. The influence of key factors, such as electrolyte composition and current/potential modes, on alloy codeposition, elemental and phase composition, structure, and deposition efficiency is discussed. The magnetic properties, electrocatalytic behavior, and corrosion resistance of the deposited films are also shown, highlighting their relevance for high-performance applications. Full article

We report, for the first time, waimirite-(Y) in Egypt. This is only the third reported occurrence of this mineral in the world. This observation arose during our study of the rare earth element (REE) mineralization associated with the Neoproterozoic rare-metal granite intrusion in Wadi Abu Rusheid in the Eastern Desert of Egypt. The principal lanthanide and yttrium (Y) hosts in the area are waimirite-(Y) and bastnäsite-(Ce) in leucogranite and bastnäsite-(Y) in adjacent metasedimentary country rock. The leucogranite is a strongly fractionated, metaluminous to weakly peraluminous (A/CNK = 0.98–1.03), medium- to high-K calk-alkaline I-type granite. The metasediments are composed of upper greenschist to lower amphibolite-grade biotite schists with variable amounts of amphibole, graphite, and garnet. Leucogranite contains accessory Li-bearing mica, garnet, zircon, fluorite, and columbite in addition to the REE minerals. It is enriched by three orders of magnitude relative to primitive mantle in Li, Rb, Th, Ta, Nb, Pb, U, and Sn; relative to these highly enriched elements the concentrations of Sr, Ba, Ga, Zr, Hf, and Y are notably low. The REE patterns of most samples show strong enrichment in heavy relative to light REE but occasional samples have light REE-enriched patterns controlled by accessory REE minerals, and all display strong negative Eu anomalies (Eu/Eu* ≤ 0.05). The whole-rock chemistry of the metasedimentary units are different; relative to average upper continental crust they show enrichments of one to two orders of magnitude in Li, Rb, Pb, Sn, Cs, and sometimes Cr and Zn. The REE patterns of the metasedimentary units are nearly flat, with some samples showing negative Eu anomalies. Waimirite-(Y), nominally YF₃, also contains several weight percent each of Yb, Dy, and Er. The empirical formula (based on one cation) is (Y_0.55Ce_0.02Pr_0.01Nd_0.02Sm_0.02Gd_0.02Dy_0.05Er_0.04Yb_0.05Th_0.05Ca_0.16Pb_0.01)_∑1.00(F_2.48O_0.52)_∑3.00. Bastnäsite-(Ce) in leucogranite samples, nominally Ce(CO₃)F, also has several weight percent each of Nd₂O₃ and La₂O₃. The REE host in metasedimentary rocks is bastnäsite-(Y), nominally Y(CO₃)F, but also rich in Nd₂O₃ (11–19 wt.%) and La₂O₃ (4–14 wt.%). It is intimately associated with fluorophlogopite. The geochemical, mineralogical, and textural evidence indicates that waimirite-(Y) and bastnäsite-(Ce) in leucogranite crystallized from granite-derived F- and CO₂-bearing hydrothermal fluids, whereas the source of Y for growth of the bastnäsite-(Y) in the metasedimentary rocks is unclear; the large negative Ce anomaly in bastnäsite-(Y) suggests an oxidizing supergene setting. Despite their proximity, if there is a genetic connection between the mineralization in the granite and in its country rocks, the relationship is not evident from elemental patterns or host mineralogy. Full article

The high reactivity of lanthanide metals poses a challenge to the electrochemical anodizing of surfaces for nanostructured coatings. This paper presents the first systematic experimental investigation of anodic oxidation of lanthanide gadolinium in aqueous solutions of citric, boric, oxalic, and tartaric acids. The voltage-current-time responses of anodizing of gadolinium, Al/Gd and Al/Nb/Gd systems were investigated. Anodic thin films were characterized using modern analysis techniques: SEM, FIB, and EDX. Morphology and voltage-current-time response analysis of anodized Al/Nb/Gd systems made it possible to establish the niobia cork-like effect and to develop a growth model. Full article

2,9-Bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen)-based ligands show great promise in the separation of trivalent lanthanides and actinides. Experimental studies have shown that americium forms stronger complexes with the BTPhen ligands than europium; most theoretical studies have so far failed to reproduce these results. In the current study, three different metal forms (the naked cation, its nitrate or perchlorate salts and tetraaqua solvated salts) were used to study different complexation reactions. It was shown that in the case of naked cations and salts, europium forms the most stable complex with the 2,9-bis(1,2-triazin-3-yl)-1,10-phenanthroline ligand in all of the reactions compared. However, europium is also more strongly interacting (compared to americium) with anions and water molecules in the tetraaquatrinitrato or tetraaquatriperchlorato complexes. That shifts the energies of reactions like Am(NO₃)₃·4H₂O + [Eu(H₂O)₄BTPhen]³⁺ = [Am(H₂O)₄BTPhen]³⁺ + Eu(NO₃)₃·4H₂O in favor of the americium being complexed with BTPhen and europium with anions and water. Therefore, the americium complexes with BTPhen become the more stable form, in an agreement with the experimental studies. Comparison of counterion influence (nitrate vs. perchlorate) indicates that bigger preference for americium over europium complexation corresponds to the nitrate complexes and stems mainly from the fact that in M(NO₃)₃(H₂O)₄ europium is stabilized more than in M(ClO₄)₃(H₂O)₄. Full article

With the discovery of amorphous oxide semiconductors, a new era of electronics opened. Indium gallium zinc oxide (IGZO) overcame the problems of amorphous and poly-silicon by reaching mobilities of ~10 cm²/Vs and demonstrating thin-film transistors (TFTs) are easy to manufacture on transparent and flexible substrates. However, mobilities over 30 cm²/Vs have been difficult to reach and other materials have been introduced. Recently, polycrystalline In₂O₃ has demonstrated breakthroughs in the field. In₂O₃ TFTs have attracted attention because of their high mobility of over 100 cm²/Vs, which has been achieved multiple times, and because of their use in scaled devices with channel lengths down to 10 nm for high integration in back-end-of-the-line (BEOL) applications and others. The present review focuses first on the material properties with the understanding of the bandgap value, the importance of the position of the charge neutrality level (CNL), the doping effect of various atoms (Zr, Ge, Mo, Ti, Sn, or H) on the carrier concentration, the optical properties, the effective mass, and the mobility. We introduce the effects of the non-parabolicity of the conduction band and how to assess them. We also introduce ways to evaluate the CNL position (usually at ~E_C + 0.4 eV). Then, we describe TFTs’ general properties and parameters, like the field effect mobility, the subthreshold swing, the measurements necessary to assess the TFT stability through positive and negative bias temperature stress, and the negative bias illumination stress (NBIS), to finally introduce In₂O₃ TFTs. Then, we will introduce vacuum and non-vacuum processes like spin-coating and liquid metal printing. We will introduce the various dopants and their applications, from mobility and crystal size improvements with H to NBIS improvements with lanthanides. We will also discuss the importance of device engineering, introducing how to choose the passivation layer, the source and drain, the gate insulator, the substrate, but also the possibility of advanced engineering by introducing the use of dual gate and 2 DEG devices on the mobility improvement. Finally, we will introduce the recent breakthroughs where In₂O₃ TFTs are integrated in neuromorphic applications and 3D integration. Full article