Rare earth incorporated electrode materials for advanced energy storage

Anode-Free Lithium-Sulfur Batteries with a Rare-Earth Triflate as a Dual-Function Electrolyte Additive

Anode-free lithium-sulfur batteries feature a cell design with a fully lithiated cathode and a bare current collector as an anode to control the total amount of lithium in the cell. The lithium stripping and deposition are key factors in designing an anode-free full cell to realize a practical cell configuration. To realize effective anode protection and achieve a good performance of the anode-free full cell, manipulation of the electrolyte chemistry toward the modification of the solid-electrolyte interphase on the anode is considered a feasible approach. In this study, the use of neodymium triflate, Nd(OTf)3, as a dual-function electrolyte additive is demonstrated to promote homogeneous catalysis on the cathode conversion reactions and the anode stabilization. Nd(OTf)3 not only facilitates the conversion reaction by promoting the polysulfide adsorption but also effectively protects the lithium-metal anode and stabilizes the lithium stripping and deposition during cycling. With this electrolyte modification, both Li∥Li2S half cells and Ni∥Li2S anode-free full cells support a high areal capacity of 5.5-7.0 mA h cm-2 and maintain a high Coulombic efficiency of 94-95% during cycling.

All-in-one strategy to develop a near-infrared triggered multifunctional bioactive magnesium phosphate bone cement for bone repair

Bone cement is widely used in clinical with optimistic filling and mechanical properties. However, the setting time of bone cement is difficult to accurately control, and the existing bone cements exhibit limited therapeutic functionalities. In response to these challenges, we designed and synthesized Nd-doped whitlockite (Nd-WH), endowing bone cement with photothermal-responsive and fluorescence imaging capabilities. The doping amount and photothermal properties of Nd-doped whitlockite were studied, and the composite bone cement was prepared. The results showed that the setting time of bone cement could be regulated by near infrared irradiation, and the multiple functions of promoting osteogenic differentiation, antibacterial and anti-tumor could be realized by adjusting the power and irradiation time of near infrared. By incorporating Nd-doped whitlockite and bone cement, we developed an all-in-one strategy to achieve setting time control, enhanced osteogenic ability, tumor cell clearance, bacterial clearance, and bone tissue regeneration. The optimized physical and mechanical properties of composite bone cement ensure adaptability and plasticity. In vitro and in vivo experiments validated the effectiveness of this bone cement platform for bone repair, tumor cell clearance and bacterial clearance. The universal methods to regulate the setting time and function of bone cement by photothermal effect has potential in orthopedic surgery and is expected to be a breakthrough in the field of bone defect repair. Further research and clinical validation are needed to ensure its safety, efficacy and sustainability. STATEMENT OF SIGNIFICANCE: Bone cement is a valuable clinical material. However, the setting time of bone cement is difficult to control, and the therapeutic function of existing bone cement is limited. Various studies have shown that the bone repair capacity of bone cements can be enhanced by synergistic stimulatory effects in vivo and ex vivo. Unfortunately, most of the existing photothermal conversion materials are non-degradable and poorly biocompatible. This study provides a bone-like photothermal conversion material with photothermal response and fluorescence imaging properties, and constructed a platform for integrated regulation of the setting time of bone cement and diversification of its functions. Therefore, it helps to design multi-functional bone repair materials that are more convenient and effective in clinical operation.

Synergistic enhancement of oxygen vacancy enrichment and morphology regulation in CeO2-NiCo2O4 heterostructure catalysts for high-performance cathodes in direct borohydride-hydrogen peroxide fuel cells

Hydrogen peroxide (H2O2) emerges as a viable oxidant for fuel cells, necessitating the development of an efficient and cost-effective electrocatalyst for the hydrogen peroxide reduction reaction (HPRR). In this study, we synthesized a self-supporting, highly active HPRR electrocatalyst comprising two morphologically distinct components: CeO2-NiCo2O4 nanowires and CeO2-NiCo2O4 metal organic framework derivatives, via a two-step hydrothermal process followed by air calcination. X-ray diffraction and transmission electron microscopy analysis confirmed the presence of CeO2 and NiCo2O4, revealing the amalgamated interface between them. CeO2 exhibits multifunctionality in regulating the surface electronic configuration of NiCo2O4, fostering synergistic connections, and introducing oxygen deficiencies to enhance the catalytic efficacy in HPRR. Electrochemical measurements demonstrate a reduction current density of 789.9 mA·cm-2 at -0.8 V vs. Ag/AgCl. The assembly of direct borohydride-hydrogen peroxide fuel cell (DBHPFC) exhibits a peak power density of 45.2 mW·cm-2, demonstrating durable stability over a continuous operation period of 120 h. This investigation providing evidence that the fabrication of heterostructured catalysts based on CeO2 for HPRR is a viable approach for the development of high-efficiency electrocatalysts in fuel cell technology.

Tumor Microenvironment-Regulating Two-Photon Probe Based on Bimetallic Post-Coordinated MOF Facilitating the Dual-Modal and Deep Imaging-Guided Synergistic Therapies

The intricate tumor microenvironment (TME) always brings about unsatisfactory therapeutic effects for treatments, although nanomedicines have been demonstrated to be highly beneficial for synergistic therapies to avoid the side effects caused by the complexity and heterogeneity of cancer. Developing nanotheranostics with the functionalities of both synergistic therapies and TME regulation is a good strategy but is still in its infancy. Herein, an "all-in-one" nanoplatform for integrated diagnosis and treatment, namely, Carrier@ICG@DOX@FA (CIDF), is constructed. Benefiting from the bimetallic coordination of Eu3+-HTHA (4,4,4-trifluoro-1-(9-hexylcarbazol-3-yl)-1,3-butanedione) and Fe3+ with the ligands in UiO-67, CIDF can simultaneously achieve two-photon fluorescence imaging, fluorescent lifetime imaging in deep tumors, and regulation of TME. Owing to its porosity, CIDF can encapsulate indocyanine green as photosensitizers and doxorubicin as chemotherapeutic agent, further realizing light-controlled drug release. Moreover, CIDF exhibited good biocompatibility and tumor targeting by coating with folic-acid-modified polymers. Both in vitro and in vivo experiments demonstrate the excellent therapeutic efficacy of CIDF through dual-modal-imaging-guided synergistic photothermal-, photodynamic-, and chemotherapy. CIDF provides a new paradigm for the construction of TME-regulated synergistic nanotheranostics and realizes the complete elimination of tumors without recurrence.

Impact of Y2O3 Nanosheets on the Microstructural Characteristics of Alq3 Prepared via the Co-precipitation Route for Enhancement of Photodiode Performance

In the present study, tris-(8-hydroxyquinoline) aluminum (Alq₃) and tris-(8-hydroxyquinoline) aluminum/yttrium oxide Alq₃/Y₂O₃ were synthesized by a facile chemical route. The crystal structure, surface morphological nature, and particle size were identified by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) micrographs. Ag/Alq₃/p-Si/Al and Ag/Alq₃:Y₂O₃/p-Si/Al diodes were fabricated by the thermal evaporation technique and the electrical characteristics were evaluated from the I-V plots in dark and under illumination intensity. Thermionic emission theory, Cheung-Cheung, and Nord model have been applied to define the main electronic parameters like series resistance (R_s), barrier height (ϕ_b), and ideality factor (n). The hybrid Ag/Alq₃:Y₂O₃/p-Si/Al diode revealed a nonideal behavior with high shunt resistance R_sh and good photocurrent sensitivity. The C/G-V analysis indicated that both C and G are strongly affected by the presence of trapped charge carriers at the interface states. The obtained results indicated that R_s was decreased whereas the carrier concentration (N_a) was increased by loading Y₂O₃ nanosheets.

Rare Earth Elements (REEs) Adsorption and Detoxification Mechanisms in Cell Wall Polysaccharides of Phytolacca americana L

The cell wall (CW) is critical for the accumulation of heavy metals in metal-tolerant plants. Polysaccharides, the main component of the CW, contribute significantly to the immobilization of heavy metals. However, the mechanisms of rare earth elements (REEs) adsorption and detoxification by polysaccharides in the cell walls of Phytolacca americana L. (P. americana) remain unclear. In this work, we explored the binding sites of REEs and the modifications to polysaccharides in the cell walls of roots and leaves in P. americana, in order to elucidate the adsorption and fixation mechanism of REEs by the cell wall. Our findings indicated that up to 40.7% and 48.1% of cell-wall-bound REEs were present in the root and leaf pectin, respectively. The removal of pectin led to a 39.8% and 23.6% decrease in the maximum adsorption of REEs in the CW, suggesting that pectin was the main binding site for REEs in the cell walls of P. americana. Hydroxyl (-OH) and carboxyl (-COOH) groups in the cell wall interacted mainly with REEs ions under stress conditions, which played a key role in REEs binding. An obvious REEs fractionation was found during the various fractions of the CW, and all fractions of the root cell wall were enriched with HREEs, whereas all fractions of the leaf cell wall were enriched with LREEs. Moreover, P. americana modulated cell wall composition in reaction to REEs stress. In conclusion, cell wall pectin is the main binding site of REEs, and the functional groups on the cell wall play a significant role in the binding of REEs. At the same time, plants can control the selective adsorption and fixation of REEs by adjusting the composition of cell walls. This study offers valuable insights into the mechanisms of REEs adsorption and fixation in cell walls of P. americana, contributing to a theoretical basis for the bioremediation of REEs pollution.

Strain-Negligible Eu2+ Doping Enabled Color-Tunable Harsh Condition-Resistant Perovskite Nanocrystals for Superior Light-Emitting Diodes

Cesium lead halide (CsPbX₃, X = Br, Cl, I) perovskite nanocrystals (NCs) possess tunable band gaps across the entire visible spectral range and are promising for various optoelectronic device applications. However, poor performance in adverse conditions limits their further development in practical optoelectronics. Herein, highly stable perovskite NCs are developed by doping europium(II) (Eu²⁺) into the B-site of CsPbBr₃ with negligible lattice distortion/strain. Eu²⁺-doped CsPbBr₃ NCs exhibit tunable green-to-cyan emissions, high photoluminescence quantum yield, and good resistance to harsh conditions, including ultraviolet irradiation, erosion of moisture, and corrosion of polar solvent molecules. In particular, the thermal stability of CsPbBr₃ NCs after Eu²⁺ doping is greatly enhanced under continuous heating in air, while exhibiting the emissions of Eu²⁺. Furthermore, a Eu²⁺-doped CsPbBr₃ NC-based cyan light-emitting diode is fabricated, which exhibits narrow exciton emission driven under different current densities. This work would open the avenue to develop the rational lanthanide ion doping strategy for further advancing perovskite nanomaterials toward practical applications.

Highly efficient Ni-Mo-P composite rare earth elements electrode as electrocatalytic cathode for oil-based drill sludge treatment

It is considered an effective strategy to improve electrochemical performance that introducing rare elements into metal catalysts, which would provide abundant electrochemical active sites and be a benefit for redox reactions. A new Ni-Mo-P composite electrode material modified with rare earth elements (light rare earth Nd and heavy rare earth Yb) was prepared, evaluating the current density of direct current electrodeposition, the doping ratio of Yb and Nd, and the cyclic voltammetry deposition (CVD) cycle numbers on electrode structure and electrochemical performance. The results showed that the electrode has the most obvious amorphous state, the lowest hydrogen evolution overpotential (41.5 mV vs Ag/AgCl) and charge transfer resistance (15.74 Ω/cm²), and remarkable stability when the molar ratio of Yb and Nd was 8:2 and the 20 cycle numbers under the CVD condition. The electrochemical performance and characterization of the electrode showed that there was a good synergistic effect between rare earth elements (Yb, Nd) and Ni-Mo-P alloys. The oil-based drill sludge (OBDS) treatment indicated that the organic matter content is significantly reduced by using the above-modified electrode as the cathode, and the COD and petroleum removal rate can reach up to 85.4 ± 1.2% and 66.2 ± 5.9%. The effect of degradation for aliphatic hydrocarbon was better than aromatic hydrocarbons and no other intermediates are produced during the degradation, which may eventually mineralize the organic matter. This research provided technical support for the preparation of new Ni-Mo-P electrodes modified with rare earth elements and confirmed that electrocatalytic technology was a suitable method for OBDS treatment.

Rare Earth-Based Nanomaterials for Supercapacitors: Preparation, Structure Engineering and Application

Supercapacitors (SCs) can effectively alleviate problems such as energy shortage and serious greenhouse effect. The properties of electrode materials directly affect the performance of SCs. Rare earth (RE) is known as "modern industrial vitamins", and their functional materials have been listed as key strategic materials. In the past few years, the number of scientific reports on RE-based nanomaterials for SCs has increased rapidly, confirming that adding RE elements or compounds to the host electrode materials with various nanostructured morphologies can greatly enhance their electrochemical performance. Although RE-based nanomaterials have made rapid progress in SCs, there are very few works providing a comprehensive survey of this field. In view of this, a comprehensive overview of RE-based nanomaterials for SCs is provided here, including the preparation methods, nanostructure engineering, compounds, and composites, along with their capacitance performances. The structure-activity relationships are discussed and highlighted. Meanwhile, the future challenges and perspectives are also pointed out. This Review can not only provide guidance for the further development of SCs but also arouse great interest in RE-based nanomaterials in other research fields such as electrocatalysis, photovoltaic cells, and lithium batteries.

Erbium-Doped GQD-Embedded Coffee-Ground-Derived Porous Biochar for Highly Efficient Asymmetric Supercapacitor

A nanocomposite with erbium-doped graphene quantum dots embedded in highly porous coffee-ground-derived biochar (Er-GQD/HPB) was synthesized as a promising electrode material for a highly efficient supercapacitor. The HPB showed high porosity, with a large surface area of 1295 m2 g−1 and an average pore size of 2.8 nm. The 2–8-nanometer Er-GQD nanoparticles were uniformly decorated on the HPB, subsequently increasing its specific surface area and thermal stability. Furthermore, the intimate contact between the Er-GQDs and HPB significantly reduced the charge-transfer resistance and diffusion path, leading to the rapid migration of ions/electrons in the mesoporous channels of the HPB. By adding Er-GQDs, the specific capacitance was dramatically increased from 337 F g−1 for the pure HPB to 699 F g−1 for the Er-GQD/HPB at 1 A g−1. The Ragone plot of the Er-GQD/HPB exhibited an ultrahigh energy density of 94.5 Wh kg−1 and a power density of 1.3 kW kg−1 at 1 A g−1. Furthermore, the Er-GQD/HPB electrode displayed excellent cycling stability, and 81% of the initial capacitance remained after 5000 cycles. Our results provide further insights into a promising supercapacitance material that offers the benefits of both fast ion transport from highly porous carbons and electrocatalytic improvement due to the embedment of Er-doped GQDs to enhance energy density relative to conventional materials.

A holistic approach for the recovery of rare earth elements and scandium from secondary sources under a circular economy framework - A review

Limited natural resources and a continuous increase in the demand for modern technological products, is creating a demand and supply gap for rare earth elements (REEs) and Sc. There is therefore a need to adopt the sustainable approach of the circular economy system (CE). In this review, we defined six steps required to close the loop and recover REEs, using a holistic approach. Recent statistics on REEs and Sc demand and the number of waste generations are reported and studies on more environmentally friendly, economic, and/or efficient recovery processes are summarized. Pilot-scale recovery facilities are described for several types of secondary sources. Finally, we identify obstacles to closing the REE loop in a circular economy and the reasons why secondary sources are not preferred over primary sources. Briefly, recovery from secondary sources should be environmentally and economically friendly and of an acceptable standard concerning final product quality. However, current technologies for recovery from for secondary sources are limiting and technology needs will vary depending on the source type. The quality/purity of the recovered metals should be proven so that they do not result in any adverse effects on the product quality, when they are being used as secondary raw material. In addition, for industrial-scale facilities, process improvements are required that consider environmental conditions.

Fabrication of honeycomb-structured composite material of Pr2O3, Co3O4, and graphene on nickel foam for high-stability supercapacitors

The Pr2O3/Co3O4/rGO/NF electrode has been prepared by hydrothermal method and annealing process, with high specific capacitance and excellent cycle stability.

Postsynthetic of MIL-101-NH2 MOFs supported on PVDF membrane for REEs recovery from waste phosphor

With the increasing demand for rare earth elements (REEs) due to their wide application in high technology, their recovery and separation from waste sources has gradually come onto the agenda. Herein, a new kind of MIL-101-NH₂ (M1N) MOF functionalized with diethanol anhydride (DGA) incorporated into a polyvinylidene fluoride (PVDF) membrane (DGA-M1N@PVDF) has been fabricated for the sorption of REEs from a simulated acid leaching solution of waste phosphor, which contains a large amount of REEs. FTIR, TGA, XRD, fluorescence spectra and XPS analysis were used to characterize the synthesized composite membrane. Batch tests were employed to determine the optimal sorption conditions for Y and Eu adsorbed on DGA-M1N@PVDF adsorbent, such as pH (1–5), content of M1N MOFs (0–40 wt%), contact time (10–180 min) and ion concentration (0–20 mg L⁻¹). Maximum adsorption capacities for Y and Eu on DGA-M1N@PVDF reached 991.7 μg g⁻¹ and 98.76 μg g⁻¹ for trace REE solution, respectively. Moreover, a pseudo-second-order kinetic model accurately described the sorption process, and the plotted isothermal data indicated that the Langmuir model was more suitable than the Freundlich model for Y and Eu sorption with monolayer and chemical adsorption. Meanwhile, FTIR and XPS analyses revealed that the Y and Eu adsorption on the DGA-M1N@PVDF composite membrane was mainly caused by the N and O atoms of the –CONH or –COOH groups coordinated with metal ions. Furthermore, after five cycles, the recovery efficiency by DGA-M1N@PVDF for REEs remains above 82% and the XRD patterns were consistent with the original sample, which implied that the DGA-M1N@PVDF membrane has preferable stability, recyclability and good efficiency in REE separation from waste phosphor solutions.

A new kind DGA modified MIL-101-NH₂ MOFs supported on PVDF composite membrane (DGA-M1N@PVDF) was synthesized, which had superior selectivity, good adsorption capacity and good recycling performance on REEs in waste phosphor.

Gram-Scale Synthesis of Nanosized Li3 HoBr6 Solid Electrolyte for All-Solid-State Li-Se Battery

Rare earth (RE) based halide solid electrolytes (HEs) are recently considered as research hotspots in the field of all-solid-state batteries (ASSBs). The RE-based HEs possess high ionic conductivity, credible deformability, and good stability, which can bring excellent electrochemical performances for ASSBs. However, the conventional synthetic methods of RE HEs are a mechanochemical process and co-melting strategy, both approaches require expensive raw materials and sophisticated equipment. Therefore, a lot of research work is required to promote the preparation methods for these promising SSEs in ASSBs. Thus, a vacuum evaporation-assisted synthesis method is developed for the massive synthesis of HEs. The as-prepared Li₃ HoBr₆ (LHB) has a high lithium-ion conductivity close to the mS cm^-1 level and the LHB-based Li-Se ASSBs can be assembled by cold pressing. Theoretical calculations have revealed that the Li migrations are highly preferred in Li₃ HoBr₆ owing to the low energy cost and high tolerance of stable structure. The tetrahedral and octahedral pathways are responsible for Li migrations in short and long ranges, respectively. The results show that the LHB-based Li-Se battery has good stability and rate performance, indicating that LHB has potential application in the field of ASSBs.

A novel battery separator coated by a europium oxide/carbon nanocomposite enhances the performance of lithium sulfur batteries

Lithium sulfur (Li-S) batteries represent one of the most promising future power batteries due to their remarkable advantages of low cost and ultrahigh theoretical energy density. However, the commercial applications of Li-S batteries have long been plagued by the shuttling effect of polysulfides and sluggish redox kinetics of these species. Herein, we designed a novel battery separator coated by a europium oxide-doped porous Ketjen Black (Eu₂O₃/KB) and tested its performance for the Li-S batteries for the first time. Experimental results and theoretical calculations reveal that the improved electrochemical performance can be attributed to the presence of Eu₂O₃. The strong binding effect between Eu₂O₃ and polysulfides is demonstrated in two aspects: (1) there exist strong interactions between Eu₂O₃ as a Lewis acid and polysulfides of strong Lewis basicity; (2) Eu₂O₃ with oxygen-vacancy defects provides active sites for catalyzing polysulfide conversion and polysulfide trapping. Thus, a Li-S battery with the Eu₂O₃/KB modified separator delivers highly stable cycling performance and excellent rate capability, with the capacity decay ratio of merely 0.05% per cycle under 1 C rate during 500 cycles, and high specific capacity of 563 mAh g^-1 at 3 C rate. This work offers a meaningful exploration of the application of rare earth oxides for the modification of the separator towards high performance Li-S batteries.

Recovery of Rare Earth Elements (REEs) Using Ionic Solvents

Rare earth elements (REEs) are becoming more and more significant as they play crucial roles in many advanced technologies. Therefore, the development of optimized processes for their recovery, whether from primary resources or from secondary sources, has become necessary, including recovery from mine tailings, recycling of end-of-life products and urban and industrial waste. Ionic solvents, including ionic liquids (ILs) and deep-eutectic solvents (DESs), have attracted much attention since they represent an alternative to conventional processes for metal recovery. These systems are used as reactive agents in leaching and extraction processes. The most significant studies reported in the last decade regarding the recovery of REEs are presented in this review.

A new neodymium-phosphine compound for supercapacitors with long-term cycling stability

A new neodymium-phosphine compound (Nd-(Ph)3P) was used for the first time as an electrode for supercapacitors and exhibited an extraordinary capacitance of 951 F g-1 at 0.5 A g-1 with a high capacitance retention of 96% after 10 000 cycles at 10 A g-1, which is the highest capacitance for rare earth based materials in SCs. Such an excellent performance might be due to the fact that this material can provide plenty of electron-active sites for charge storage and electrolyte diffusion can be efficiently promoted.

Effective electro-Fenton-like process for phenol degradation on cerium oxide hollow spheres encapsulated in porous carbon cathode derived from skimmed cotton

The uniform size cerium dioxide hollow spheres which were prepared by the SiO₂ hard template method were loaded on microporous porous carbon obtained by carbonization derived from skimmed cotton (CSC) for electro-Fenton-like degradation of phenol. The microstructures of CSC/CeO₂ composite materials were characterized utilizing XRD, BET, XPS, SEM, and TEM. The electrochemical performance of the CSC/CeO₂ cathodes was studied through cyclic voltammetry and electrochemical impedance spectroscopy. The prepared CSC has a hollow tubular structure, and cerium dioxide is evenly loaded on the surface of the CSC in the form of uniform-sized hollow spheres. The CSC/CeO₂ materials have a great specific surface area (287.73 m² g^-1) and a uniform poresize. The electrochemical performance analysis demonstrated that the redox ability of the material greatly was improved by loading CeO₂ on the porous carbon surface of the skimmed cotton. The load ratio of cerium dioxide hollow spheres affects the structure and properties of CSC/CeO₂ materials. Ce³⁺ and Ce⁴⁺ were co-existed in CSC/CeO₂, which promoted the generation of H₂O₂ and ^.OH, and improved the catalytic activity of composite materials. The degradation efficiency of phenol reached 97.6% in 120 min, and the CSC/CeO₂ cathode manifested excellent stability after being experimented 20 times. CSC/CeO₂ composite material has great practical value in the treatment of phenolic wastewater and has promise for further application.

Two-Step Solvent Extraction of Radioactive Elements and Rare Earths from Estonian Phosphorite Ore Using Nitrated Aliquat 336 and Bis(2-ethylhexyl) Phosphate

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare earth elements, Mo, V, etc. might be economically exploitable, while some radioactive and toxic elements should be removed before any other downstream processing for environmental and nutritional safety reasons. All untreated hazardous elements remain in landfilled waste in much higher concentration than they occur naturally. To resolve this problem U, Th, and Tl were removed from phosphorite ore at first using liquid extraction. In the next step, REE were isolated from raffinate. Nitrated Aliquat 336 (A336[NO3]) and Bis(2-ethylhexyl) Phosphate (D2EHPA) were used in liquid extraction for comparison. An improved method for exclusive separation of radioactive elements and REEs from phosphorite ore in 2-steps has been developed, exploiting liquid extraction at different pH values.

First-Principles Study on Electronic, Magnetic, Optical, Mechanical, and Thermodynamic Properties of Semiconducting Gadolinium Phosphide in GGA, GGA+U, mBJ, GGA+SOC and GGA+SOC+U approaches

In the current article, the electronic, magnetic, and optical properties of GdP in the hypothetical zinc blende structure have been discussed by using GGA, GGA+U, mBJ, GGA+SOC, and GGA+SOC+U approaches. The energy vs volume plots in the three magnetic states suggest the ferromagnetic phase to be the stable phase of GdP. The cohesive energy calculated for GdP is negative, suggesting the stability of the compound. The electronic band structure calculations predict the binary GdP to be a direct bandgap conventional semiconductor. The optical properties confirm the semiconducting properties of GdP, and the bandgap formation follows Penn's criteria. The elastic constants also confirm the stability of the compound with ductile nature. The thermodynamic properties including Debye temperature, entropy, and specific heat capacity are studied under varying hydrostatic pressures taking into account the quasi-harmonic Debye model. The doping of Cu in the supercell of GdP results in the compound to exhibit half-metallic ferromagnetic properties. The magnetic moments calculated for Cu_xGd_1-xP (x = 0.25) are integer-valued backing its half-metallic character and fit excellent with the Slauter-Pauling rule Z_t-8. GdP in the zinc blende structure can prove a potential candidate for optoelectronic devices having better reflectivity in the UV region whereas its doped compounds have the potential to exhibit half-metallic properties useful in spintronics.

Rare-Earth Incorporated Alloy Catalysts: Synthesis, Properties, and Applications

To improve the performance of metallic catalysts, alloying provides an efficient methodology to design state-of-the-art materials. As emerging functional materials, rare-earth metal compounds can integrate the unique orbital structure and catalytic behavior of rare earth elements into metallic materials. Such rare-earth containing alloy catalysts proffer an opportunity to tailor electronic properties, tune charged carrier transport, and synergize surface reactivity, which are expected to significantly improve the performance and stability of catalysis. Despite its significance, there are only few reviews on rare earth containing alloys or related topics. This review summarizes the composition, synthesis, and applications of rare earth containing alloys in the field of catalysis. Subsequent to comprehensively summarizing and constructively discussing the existing work, the challenges and possibilities of future research on rare-earth metal compound materials are evaluated.

Study on the Effect and Mechanism of Impurity Aluminum on the Solvent Extraction of Rare Earth Elements (Nd, Pr, La) by P204-P350 in Chloride Solution

Solvent extraction is the most widely used method for separation and purification of rare earth elements, and organic extractants such as di(2-ethylhexyl) phosphoric acid (P204) and di(1-methyl-heptyl) methyl phosphonate (P350) are most commonly used for industrial applications. However, the presence of impurity ions in the feed liquid during extraction can easily emulsify the extractant and affect the quality of rare earth products. Aluminum ion is the most common impurity ion in the feed liquid, and it is an important cause of emulsification of the extractant. In this study, the influence of aluminum ion was investigated on the extraction of light rare earth elements by the P204-P350 system in hydrochloric acid medium. The results show that Al3+ competes with light rare earths in the extraction process, reducing the overall extraction rate. In addition, the Al3+ stripping rate is low and there is continuous accumulation of Al3+ in the organic phase during the stripping process, affecting the extraction efficiency and even causing emulsification. The slope method and infrared detection were utilized to explore the formation of an extraction compound of Al3+ and the extractant P204-P350 that entered the organic phase as AlCl[(HA)2]2P350(o).

Rare earth elements in drill cutting samples from off-shore oil and gas exploration activities in ultradeep waters

Rare earth elements (REEs) are essential in high technology industries and have great economic value. The monitoring of REEs concentrations in rocks from oil well drill cuttings is critical to avoid environmental contamination and evaluate new sources of these elements. However, information is scarce about the REEs concentrations in drill cuttings. In this work, the concentration of REEs in drill cuttings from oil and gas exploration wells in ultradeep coastal water of Brazilian were investigated at different depths. The drill cutting samples were submitted to microwave-assisted acid digestion prior to the determination of concentration by ICP-MS, using Rh as internal standard for calibration. The limits of quantification (LoQ) ranged from 3.3 μg kg^-1 for Ho to 198 μg kg^-1 for Sm. The accuracy was evaluated by analyzing certified reference materials for rocks. The obtained REEs concentrations agreed with the certified values, reaching 83%-105% agreement. The drill cutting depth profile analysis indicates Ce, La, Nd, Sm, and Eu concentrations up to mg kg^-1. The REEs concentrations obtained in drill cutting depth profile was analyzed by principal component analysis (PCA), and hierarchical cluster analysis (HCA) identified tendency and similarity between drill cutting samples. Three groups were formed according to the composition of the REEs. In addition, the concentration of these chemicals elements varied at different depths. The analysis of drill cuttings revealed REEs concentrations up to the mg per kg-range (ppm), potentially making this disposable material an alternative source for REEs extraction, and adding value to this material.

Scalable High-Areal-Capacity Li-S Batteries Enabled by Sandwich-Structured Hierarchically Porous Membranes with Intrinsic Polysulfide Adsorption

The key to realizing practical applications of Li-S batteries lies in scalable fabrication of cathode materials with high sulfur-loading and strong binding of lithium polysulfides (LiPSs). We report a scalable CeO₂-CNT@C porous membrane with a large porosity of 90%. Introducing CNTs is critical to increase the porosity and construct porous networks with CNTs as the skeleton and CeO₂-doped carbon as the shell. The macropores can improve the transport of Li⁺ and electrolyte, while the porous networks possess high polysulfide-adsorbing and electron-transferring ability. The CeO₂-CNT@C membrane can serve as an Al foil-free cathode and an interlayer for Li-S batteries. Moreover, CeO₂ can immobilize LiPSs and can alleviate its shuttle effect. The Li-S batteries with a sulfur loading of 6.2 mg cm^-2 deliver a capacity of 847 mA h g^-1 after 100 cycles, showing a high areal capacity of 5.25 mA h cm^-2 at a low electrolyte/sulfur ratio of 5.2 μL mg^-1.

Preparation of Carboxymethyl Cellulose-g- Poly(acrylamide)/Attapulgite Porous Monolith With an Eco-Friendly Pickering-MIPE Template for Ce(III) and Gd(III) Adsorption

Due to their high specific surface and metal-binding functional groups in their crosslinked polymeric networks, monolithic materials incorporating a porous structure have been considered one of the most efficient kinds of adsorbents for rare earth element recovery. Herein, a facile and novel monolithic multi-porous carboxymethyl cellulose-g-poly(acrylamide)/attapulgite was synthesized by free radical polymerization via green vegetable oil-in-water Pickering medium internal phase emulsion (O/W Pickering-MIPEs), which was synergically stabilized by attapulgite and tween-20. The homogenizer rotation speed and time were investigated to form stable Pickering-MIPEs. The effects of different types of oil phase on the formation of Pickering-MIPEs were investigated with stability tests and rheological characterization. The structure and composition of the porous material when prepared with eight kinds of vegetable oil were characterized by FTIR and SEM. The results indicate that the obtained materials, which have abundant interconnected porosity, are comparable to those fabricated with Pickering-HIPE templates. The adsorption experiment demonstrated that the prepared materials have a fast capture rate and high adsorption capacities for Ce(III) and Gd(III), respectively. The saturation adsorption capacities for Ce(III) and Gd(III) are 205.48 and 216.73 mg/g, respectively, which can be reached within 30 min. Moreover, the monolithic materials exhibit excellent regeneration ability and reusability. This work provides a feasible and eco-friendly pathway for the construction of a multi-porous adsorbent for adsorption and separation applications.

Beyond Lithium-Based Batteries

We discuss the latest developments in alternative battery systems based on sodium, magnesium, zinc and aluminum. In each case, we categorize the individual metals by the overarching cathode material type, focusing on the energy storage mechanism. Specifically, sodium-ion batteries are the closest in technology and chemistry to today's lithium-ion batteries. This lowers the technology transition barrier in the short term, but their low specific capacity creates a long-term problem. The lower reactivity of magnesium makes pure Mg metal anodes much safer than alkali ones. However, these are still reactive enough to be deactivated over time. Alloying magnesium with different metals can solve this problem. Combining this with different cathodes gives good specific capacities, but with a lower voltage (<1.3 V, compared with 3.8 V for Li-ion batteries). Zinc has the lowest theoretical specific capacity, but zinc metal anodes are so stable that they can be used without alterations. This results in comparable capacities to the other materials and can be immediately used in systems where weight is not a problem. Theoretically, aluminum is the most promising alternative, with its high specific capacity thanks to its three-electron redox reaction. However, the trade-off between stability and specific capacity is a problem. After analyzing each option separately, we compare them all via a political, economic, socio-cultural and technological (PEST) analysis. The review concludes with recommendations for future applications in the mobile and stationary power sectors.

Rare-earth-containing perovskite nanomaterials: design, synthesis, properties and applications

As star material, perovskites have been widely used in the fields of optics, photovoltaics, electronics, magnetics, catalysis, sensing, etc. However, some inherent shortcomings, such as low efficiency (power conversion efficiency, external quantum efficiency, etc.) and poor stability (against water, oxygen, ultraviolet light, etc.), limit their practical applications. Downsizing the materials into nanostructures and incorporating rare earth (RE) ions are effective means to improve their properties and broaden their applications. This review will systematically summarize the key points in the design, synthesis, property improvements and application expansion of RE-containing (including both RE-based and RE-doped) halide and oxide perovskite nanomaterials (PNMs). The critical factors of incorporating RE elements into different perovskite structures and the rational design of functional materials will be discussed in detail. The advantages and disadvantages of different synthesis methods for PNMs will be reviewed. This paper will also summarize some practical experiences in selecting suitable RE elements and designing multi-functional materials according to the mechanisms and principles of REs promoting the properties of perovskites. At the end of this review, we will provide an outlook on the opportunities and challenges of RE-containing PNMs in various fields.

Carbon-Coated Yttria Hollow Spheres as Both Sulfur Immobilizer and Catalyst of Polysulfides Conversion in Lithium-Sulfur Batteries

Li-S battery has tremendous application prospect on account of the high theoretical specific capacity and large energy density, while its large-scale application is impeded by the severe shuttle effect and the slow electrochemical kinetics of polysulfides conversion. Herein, the Lewis acidic yttria hollow spheres (YHS) are rationally designed as both sulfur immobilizer and catalyst of polysulfides conversion for the advanced Li-S batteries. It can be known that the Lewis acidic yttria can effectively capture the Lewis basic polysulfides and thus mitigate the shuttle effect of Li-S battery; besides, yttria shows the enhanced catalytic effect for the kinetics of interconversion reaction from polysulfides to Li₂S. As a result, either as a sulfur host or as the separator coating, yttria plays a vital part in realizing the high specific discharge capacity and good cycle stability for Li-S battery. In particular, Li-S battery with YHS@C/S cathode and YHS/CNT-0.6- modified separator (2.1 mg cm^-2 active material loading) shows a good specific discharge capacity of 912.5 mAh g^-1 at 0.5C. Even after 200 steady cycles, the discharge specific capacity can keep as 842.3 mAh g^-1, and the capacity decay rate is only 0.038% per cycle. When active material areal loading is increased to 4.24 mg cm^-2, it still maintains a considerable areal capacity of 3.79 mAh cm^-2. In consequence, the synergy of polysulfides confinement and catalytic conversion reaction provides a meaningful exploration for achieving the high performance of Li-S batteries.