Pub Date : 2025-08-06DOI: 10.1016/j.jre.2025.08.003
Chun-Hua Yan , Xiaowei Huang
This article briefly reviews the major research progress of 9 typical material fields, including rare earth luminescence materials, catalysis, rare earth materials for biomedical applications, magnetic materials, optical crystals, molecular-based materials, energy materials, metals and alloys, as well as rare earth extraction, separation and recycling in the year 2024. The aim of the review is to summarize the past and look into the future, and it will provide a basic overview of domestic work in related fields last year. Due to the abundance of content, the review strives to be concise.
{"title":"Review on progress of rare earth science and technology in 2024","authors":"Chun-Hua Yan , Xiaowei Huang","doi":"10.1016/j.jre.2025.08.003","DOIUrl":"10.1016/j.jre.2025.08.003","url":null,"abstract":"<div><div>This article briefly reviews the major research progress of 9 typical material fields, including rare earth luminescence materials, catalysis, rare earth materials for biomedical applications, magnetic materials, optical crystals, molecular-based materials, energy materials, metals and alloys, as well as rare earth extraction, separation and recycling in the year 2024. The aim of the review is to summarize the past and look into the future, and it will provide a basic overview of domestic work in related fields last year. Due to the abundance of content, the review strives to be concise.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 10","pages":"Pages 2029-2052"},"PeriodicalIF":7.2,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-08DOI: 10.1016/j.jre.2025.07.013
Zhenqian Zhang, Guangyi Sun, Xinyue Ye, Lingwei Li
The magnetic refrigeration (MR) based on the principle of magnetocaloric effect (MCE) in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology. Evidently, a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances. In this paper, the polycrystalline garnet RE3Al5O12 (RE = Tb, Dy and Ho) compounds with the cubic structure (space group: ) were prepared using the Pechini sol–gel method, and their crystal structure, magnetic properties and comprehensive magnetocaloric performances were studied. The analysis of magnetic susceptibility curves in a static magnetic field H = 0.1 T reveal that the Dy3Al5O12 undergoes antiferromagnetic transition with Néel temperature TN ≈ 2.6 K, whereas the Tb3Al5O12 and Ho3Al5O12 exhibit no features indicative of the magnetic ordering processes down to 1.8 K. The comprehensive magnetocaloric performances, namely the maximum magnetic entropy change and relative cooling power, are derived indirectly from the isothermal field-dependent magnetization data, which yield 11.72, 10.42, 7.53 J/(kg·K) and 84.56, 69.52, 70.35 J/kg for the Tb3Al5O12, Dy3Al5O12 and Ho3Al5O12 under a low field change (ΔH) of 0–2 T, respectively. The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under low ΔH make them attractive for cryogenic MR technology.
{"title":"Crystal structure, magnetic properties and cryogenic magnetocaloric performance of garnet RE3Al5O12 (RE = Tb, Dy and Ho) compounds","authors":"Zhenqian Zhang, Guangyi Sun, Xinyue Ye, Lingwei Li","doi":"10.1016/j.jre.2025.07.013","DOIUrl":"10.1016/j.jre.2025.07.013","url":null,"abstract":"<div><div>The magnetic refrigeration (MR) based on the principle of magnetocaloric effect (MCE) in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology. Evidently, a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances. In this paper, the polycrystalline garnet RE<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> (RE = Tb, Dy and Ho) compounds with the cubic structure (space group: <span><math><mrow><mi>I</mi><mi>a</mi><mover><mn>3</mn><mo>¯</mo></mover><mi>d</mi></mrow></math></span>) were prepared using the Pechini sol–gel method, and their crystal structure, magnetic properties and comprehensive magnetocaloric performances were studied. The analysis of magnetic susceptibility curves in a static magnetic field <em>H</em> = 0.1 T reveal that the Dy<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> undergoes antiferromagnetic transition with Néel temperature <em>T</em><sub>N</sub> ≈ 2.6 K, whereas the Tb<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> and Ho<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> exhibit no features indicative of the magnetic ordering processes down to 1.8 K. The comprehensive magnetocaloric performances, namely the maximum magnetic entropy change and relative cooling power, are derived indirectly from the isothermal field-dependent magnetization data, which yield 11.72, 10.42, 7.53 J/(kg·K) and 84.56, 69.52, 70.35 J/kg for the Tb<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>, Dy<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> and Ho<sub>3</sub>Al<sub>5</sub>O<sub>12</sub> under a low field change (Δ<em>H</em>) of 0–2 T, respectively. The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under low Δ<em>H</em> make them attractive for cryogenic MR technology.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 10","pages":"Pages 2195-2203"},"PeriodicalIF":7.2,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-03DOI: 10.1016/j.jre.2025.07.006
Dingding Xiang , Xiaoxin Leng , Liang Yan , Yutang Wang , Di Wang , Shu Wang , Zibin Chen , Xiaoshu Zhou
The poor wear resistance limits the applications of Ti6Al4V alloy. The additive manufactured Ti6Al4V alloy, particularly produced in the air, has issues with the poor forming quality. In this study, a rare earth compound (LaB6) was introduced to enhance both the forming quality and bio-tribological properties of Ti6Al4V alloy. The results show that adding an appropriate amount of LaB6 can reduce defects (pores). The microstructure is obviously refined due to pinning and heterogeneous nucleation effects, and the La2O3 and TiB are formed through the in-situ reactions. The sample with 4 wt% LaB6 addition exhibits excellent microhardness and bio-tribological properties. Grain refinement, dispersion strengthening and solution strengthening can significantly improve the microhardness, and the bio-tribological properties are further improved when combined with the in-situ network-structured hard TiB whisker (TiBw). This work is expected to provide reference suggestions for the development of additive manufactured titanium alloys and its application in implants.
{"title":"Improvement of forming quality, microstructure, and bio-tribological properties of additive manufactured Ti6Al4V with LaB6 addition","authors":"Dingding Xiang , Xiaoxin Leng , Liang Yan , Yutang Wang , Di Wang , Shu Wang , Zibin Chen , Xiaoshu Zhou","doi":"10.1016/j.jre.2025.07.006","DOIUrl":"10.1016/j.jre.2025.07.006","url":null,"abstract":"<div><div>The poor wear resistance limits the applications of Ti6Al4V alloy. The additive manufactured Ti6Al4V alloy, particularly produced in the air, has issues with the poor forming quality. In this study, a rare earth compound (LaB<sub>6</sub>) was introduced to enhance both the forming quality and bio-tribological properties of Ti6Al4V alloy. The results show that adding an appropriate amount of LaB<sub>6</sub> can reduce defects (pores). The microstructure is obviously refined due to pinning and heterogeneous nucleation effects, and the La<sub>2</sub>O<sub>3</sub> and TiB are formed through the <em>in-situ</em> reactions. The sample with 4 wt% LaB<sub>6</sub> addition exhibits excellent microhardness and bio-tribological properties. Grain refinement, dispersion strengthening and solution strengthening can significantly improve the microhardness, and the bio-tribological properties are further improved when combined with the <em>in-situ</em> network-structured hard TiB whisker (TiBw). This work is expected to provide reference suggestions for the development of additive manufactured titanium alloys and its application in implants.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 12","pages":"Pages 2844-2856"},"PeriodicalIF":7.2,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145594945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cerium oxide is an earth-abundant, highly researched multifunctional oxide with great technological importance and wide applications area. Trivalent rare earth (RE3+) dopants modify the defects concentration, create plenty of Ce3+⇄Ce4+ redox centres and generate numerous oxygen vacancies than the pure ceria. In the present work, CeO2 (CE), 10 mol% Gd doped ceria (Ce0.9Gd0.1O2–ẟ; CGO), and 10 mol% Sm doped ceria (Ce0.9Sm0.1O2–ẟ; CSO) were synthesized by sol–gel auto-combustion method. The phase formation, particle morphology, and elemental distribution of the synthesized powder samples were studied by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray analysis. UV-diffuse reflectance spectroscopy was used to study the optical properties of the material. The band gaps of the CE, CSO and CGO were calculated to be 2.81, 2.71 and 2.60 eV, respectively. Electrochemical impedance spectroscopy (EIS) at room temperature (RT) investigated the materials' electrical properties. The improved electrical conductivity was registered for the doped variants. CGO reaches the highest one (0.4 × 10−7 S/cm) at RT. Cyclic voltammetry (CV) was performed to study the oxidation-reduction behavior and reversibility of the ion intercalation–deintercalation process of the materials in an electrolyte solution. For the doped ceria, a threefold improved current density is observed for the cathodic part, while a small improvement is reflected in the anodic part. Specific capacitance (Csp) was calculated at the Faradaic and non-Faradaic region of the voltammograms. Csp of the materials increases in the order of CE << CSO < CGO. The highest Csp 345.16 F/g at a scan rate of 5 mV/s is obtained for the CGO. Lastly, a correlation is drawn by analysing cyclic voltammograms to conclude the applicability of the doped ceria material for room-temperature water-electrolysis in the alkaline medium.
{"title":"Effect of trivalent rare earth metal doping on structural, optical, electrical and electrochemical properties of cerium oxide ceramics","authors":"Subhadip Das, Rupesh Mondal, Kumar Sanket, Sudhin Sukumaran, Arun Chowdhury, Shantanu K. Behera, Swadesh Kumar Pratihar","doi":"10.1016/j.jre.2025.06.017","DOIUrl":"10.1016/j.jre.2025.06.017","url":null,"abstract":"<div><div>Cerium oxide is an earth-abundant, highly researched multifunctional oxide with great technological importance and wide applications area. Trivalent rare earth (RE<sup>3+</sup>) dopants modify the defects concentration, create plenty of Ce<sup>3+</sup>⇄Ce<sup>4+</sup> redox centres and generate numerous oxygen vacancies than the pure ceria. In the present work, CeO<sub>2</sub> (CE), 10 mol% Gd doped ceria (Ce<sub>0.9</sub>Gd<sub>0.1</sub>O<sub>2–<em>ẟ</em></sub>; CGO), and 10 mol% Sm doped ceria (Ce<sub>0.9</sub>Sm<sub>0.1</sub>O<sub>2–<em>ẟ</em></sub>; CSO) were synthesized by sol–gel auto-combustion method. The phase formation, particle morphology, and elemental distribution of the synthesized powder samples were studied by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray analysis. UV-diffuse reflectance spectroscopy was used to study the optical properties of the material. The band gaps of the CE, CSO and CGO were calculated to be 2.81, 2.71 and 2.60 eV, respectively. Electrochemical impedance spectroscopy (EIS) at room temperature (RT) investigated the materials' electrical properties. The improved electrical conductivity was registered for the doped variants. CGO reaches the highest one (0.4 × 10<sup>−7</sup> S/cm) at RT. Cyclic voltammetry (CV) was performed to study the oxidation-reduction behavior and reversibility of the ion intercalation–deintercalation process of the materials in an electrolyte solution. For the doped ceria, a threefold improved current density is observed for the cathodic part, while a small improvement is reflected in the anodic part. Specific capacitance (<em>C</em><sub>sp</sub>) was calculated at the Faradaic and non-Faradaic region of the voltammograms. <em>C</em><sub>sp</sub> of the materials increases in the order of CE << CSO < CGO. The highest <em>C</em><sub>sp</sub> 345.16 F/g at a scan rate of 5 mV/s is obtained for the CGO. Lastly, a correlation is drawn by analysing cyclic voltammograms to conclude the applicability of the doped ceria material for room-temperature water-electrolysis in the alkaline medium.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 12","pages":"Pages 2766-2779"},"PeriodicalIF":7.2,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145594909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-10DOI: 10.1016/j.jre.2025.06.001
Xinran Yan , Ming Zhao , Feng Jiang , Haifeng Zhu , Weinan Dong , Shengrong He , Jingjing Xia , Meixin Hong , Zhennan Wu , Xue Bai
Achieving high-efficiency photoluminescence in trivalent lanthanides (Ln3+) requires precise crystal-field perturbation to overcome parity-forbidden 4f-transitions and suppress nonradiative decay. However, realizing such control remains challenging, even in well-optimized Ln3+-doped nanocrystals. Here, by exploiting the atomically precise structure of metal nanoclusters, we demonstrate symmetry engineering in the Eu2Ti4 nanoclusters through stepwise ligand substitution (BA/Phen → FBA/Phen→ FBA/Bpy. BA: benzoicacid; Phen: 1,10-phenanthroline; FBA: p-fluorobenzoicacid; Bpy: 2,2′-bipyridine). The incorporation of FBA effectively suppresses nonradiative relaxation, while the flexible Bpy ligand induces symmetry reduction from D2d to C2v through coordination modulation, yielding a high photoluminescence quantum yield (PLQY) of 91.2% in the Ln3+ cluster systems. The transient-absorption, Judd-Ofelt theory, crystal-field analysis, and temperature-dependent photophysical studies elucidated the underlying modulation mechanisms. Furthermore, these clusters exhibit promising potential for optoelectronic applications, offering a new design strategy for high-performance luminescent materials.
{"title":"Ligand rigidity-mediated coordination symmetry engineering in lanthanide-titanium nanoclusters achieves >90% photoluminescence quantum yield","authors":"Xinran Yan , Ming Zhao , Feng Jiang , Haifeng Zhu , Weinan Dong , Shengrong He , Jingjing Xia , Meixin Hong , Zhennan Wu , Xue Bai","doi":"10.1016/j.jre.2025.06.001","DOIUrl":"10.1016/j.jre.2025.06.001","url":null,"abstract":"<div><div>Achieving high-efficiency photoluminescence in trivalent lanthanides (Ln<sup>3+</sup>) requires precise crystal-field perturbation to overcome parity-forbidden 4f-transitions and suppress nonradiative decay. However, realizing such control remains challenging, even in well-optimized Ln<sup>3+</sup>-doped nanocrystals. Here, by exploiting the atomically precise structure of metal nanoclusters, we demonstrate symmetry engineering in the Eu<sub>2</sub>Ti<sub>4</sub> nanoclusters through stepwise ligand substitution (BA/Phen → FBA/Phen→ FBA/Bpy. BA: benzoicacid; Phen: 1,10-phenanthroline; FBA: p-fluorobenzoicacid; Bpy: 2,2′-bipyridine). The incorporation of FBA effectively suppresses nonradiative relaxation, while the flexible Bpy ligand induces symmetry reduction from <em>D</em><sub>2d</sub> to <em>C</em><sub>2v</sub> through coordination modulation, yielding a high photoluminescence quantum yield (PLQY) of 91.2% in the Ln<sup>3+</sup> cluster systems. The transient-absorption, Judd-Ofelt theory, crystal-field analysis, and temperature-dependent photophysical studies elucidated the underlying modulation mechanisms. Furthermore, these clusters exhibit promising potential for optoelectronic applications, offering a new design strategy for high-performance luminescent materials.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 8","pages":"Pages 1590-1600"},"PeriodicalIF":5.2,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.jre.2025.04.027
Xiangjun Liu , Zhongqiao Ma , Changqiao Yang , Xiang Li , Jichun Yang , Huiping Ren , Hui Ma
Based on first-principles calculation framework, the surface model, anodic dissolution, cathodic oxygen absorption reaction, and other related electrochemical corrosion models of Fe-Ce system were constructed, and the influencing mechanism Ce doping on the corrosion resistance of Fe-Ce system in the Cl medium environment was analyzed. The results show that Ce doping on the first surface and subsurface inhibits the ionization of Fe atoms and greatly promotes the repassivation process of Fe matrix. Ce doping on the first layer is conducive to preventing the detachment of surface Fe atoms from Fe matrix and delaying the occurrence of corrosion. Ce atoms in the subsurface effectively increase the difficulty of Fe atoms detaching from the matrix at high Cl concentrations. When O diffusion is the controlling link of oxygen absorption reaction, Ce doping has no effects on the reaction rate of cathodic oxygen absorption. Ce doping enhances the electrochemical stability of Fe(100)1 and reduces the anodic dissolution rate of Fe matrix, thereby improving its corrosion resistance.
{"title":"First-principles analysis of effects of cerium doping on electrochemical corrosion behaviors of steel","authors":"Xiangjun Liu , Zhongqiao Ma , Changqiao Yang , Xiang Li , Jichun Yang , Huiping Ren , Hui Ma","doi":"10.1016/j.jre.2025.04.027","DOIUrl":"10.1016/j.jre.2025.04.027","url":null,"abstract":"<div><div>Based on first-principles calculation framework, the surface model, anodic dissolution, cathodic oxygen absorption reaction, and other related electrochemical corrosion models of Fe-Ce system were constructed, and the influencing mechanism Ce doping on the corrosion resistance of Fe-Ce system in the Cl medium environment was analyzed. The results show that Ce doping on the first surface and subsurface inhibits the ionization of Fe atoms and greatly promotes the repassivation process of Fe matrix. Ce doping on the first layer is conducive to preventing the detachment of surface Fe atoms from Fe matrix and delaying the occurrence of corrosion. Ce atoms in the subsurface effectively increase the difficulty of Fe atoms detaching from the matrix at high Cl concentrations. When O diffusion is the controlling link of oxygen absorption reaction, Ce doping has no effects on the reaction rate of cathodic oxygen absorption. Ce doping enhances the electrochemical stability of Fe(100)<sub>1</sub> and reduces the anodic dissolution rate of Fe matrix, thereby improving its corrosion resistance.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 8","pages":"Pages 1758-1768"},"PeriodicalIF":5.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-29DOI: 10.1016/j.jre.2025.04.020
L. Schieren , S. Semsari Parapari , T. Tomše , K. Žužek , S. Šturm , S. Kobe , C. Burkhardt
A single-phase Nd2Fe14B powder was prepared from end-of-life (EOL) wind turbine magnets by a combination of hydrogen processing of magnetic scrap (HPMS) and selective leaching with citric acid. The impact of leaching time on chemical composition, particle size and magnetic properties was investigated. Due to the low reduction potential of rare earth element (REE), the Nd-rich phase was preferentially leached. The use of an acid concentration of 0.5 mol/L, a solid to liquid ratio of 1/10 and a leaching time of 30 min was sufficient to leach the Nd-rich phase. Atomic resolution transmission electron microscopy was employed to examine the surface structure and chemistry of the leached Nd2Fe14B powder. It is revealed that the leaching process affects not only the Nd-rich phase but also the matrix grains, resulting in the formation of a predominant oxygen-rich amorphous reaction layer, 25 nm thick. However, the oxygen content is reduced from 3500 to 2500 ppm and the magnetic saturation is increased by 8%. This method is a promising addition to the HPMS process, as the powder can be mixed with fresh, unoxidized grain boundary phase to produce recycled magnets with high remanence.
{"title":"Evaluating citric acid as a selective leaching agent to extract Nd2Fe14B matrix phase from end-of-life magnets","authors":"L. Schieren , S. Semsari Parapari , T. Tomše , K. Žužek , S. Šturm , S. Kobe , C. Burkhardt","doi":"10.1016/j.jre.2025.04.020","DOIUrl":"10.1016/j.jre.2025.04.020","url":null,"abstract":"<div><div>A single-phase Nd<sub>2</sub>Fe<sub>14</sub>B powder was prepared from end-of-life (EOL) wind turbine magnets by a combination of hydrogen processing of magnetic scrap (HPMS) and selective leaching with citric acid. The impact of leaching time on chemical composition, particle size and magnetic properties was investigated. Due to the low reduction potential of rare earth element (REE), the Nd-rich phase was preferentially leached. The use of an acid concentration of 0.5 mol/L, a solid to liquid ratio of 1/10 and a leaching time of 30 min was sufficient to leach the Nd-rich phase. Atomic resolution transmission electron microscopy was employed to examine the surface structure and chemistry of the leached Nd<sub>2</sub>Fe<sub>14</sub>B powder. It is revealed that the leaching process affects not only the Nd-rich phase but also the matrix grains, resulting in the formation of a predominant oxygen-rich amorphous reaction layer, 25 nm thick. However, the oxygen content is reduced from 3500 to 2500 ppm and the magnetic saturation is increased by 8%. This method is a promising addition to the HPMS process, as the powder can be mixed with fresh, unoxidized grain boundary phase to produce recycled magnets with high remanence.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 11","pages":"Pages 2538-2550"},"PeriodicalIF":7.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-28DOI: 10.1016/j.jre.2025.04.019
Zahra Adineh, Ahmad Gholizadeh, Sakineh Hosseini
Rare earth metals and transition metals co-substitution have been shown to tailor the physical properties of BiFeO3. In this work, a series of Bi1–xRExFe1–xZrxO3 (RE = La, Pr, Nd, Sm; x = 0.00, 0.03, 0.06) multiferroic ferrites was synthesized using the sol–gel method. To gain comprehensive insights into these materials, we employed a range of characterization techniques, including X-ray diffraction, Raman and Fourier transform infrared spectroscopies, field emission scanning electron microscopy, UV–Vis spectroscopy, and a vibrating sample magnetometer. Our analysis reveals a rhombohedral crystal structure (R3c space group) for the synthesized ferrites. Notably, we observe a substantial decrease in the optical band gap as the RE/Zr co-substitution increases. Further investigation into the magnetic properties shows a remarkable transition from antiferromagnetic to ferromagnetic behavior, which we attribute to the disruption of the long-range periodicity of the spin cycloid and 4f-3d orbital interactions. In addition, we tested the photocatalytic performance of the RE/Zr co-substituted BiFeO3 nanoparticles for the degradation of methyl orange dye under sunlight. The results are quite impressive, with degradation efficiency reaching up to 100% at 40 min by the Bi1–xRExFe1–xZrxO3 (RE = La, Sm). Overall, our study demonstrates the vast potential of Bi1–xRExFe1–xZrxO3 ferrites in various fields, including optics, magnetism, water treatment, and environmental preservation.
{"title":"Exploring influence of light rare-earth elements and zirconium co-substitution on physical and photocatalytic behavior of BiFeO3","authors":"Zahra Adineh, Ahmad Gholizadeh, Sakineh Hosseini","doi":"10.1016/j.jre.2025.04.019","DOIUrl":"10.1016/j.jre.2025.04.019","url":null,"abstract":"<div><div>Rare earth metals and transition metals co-substitution have been shown to tailor the physical properties of BiFeO<sub>3</sub>. In this work, a series of Bi<sub>1–<em>x</em></sub>RE<sub><em>x</em></sub>Fe<sub>1–<em>x</em></sub>Zr<sub><em>x</em></sub>O<sub>3</sub> (RE = La, Pr, Nd, Sm; <em>x</em> = 0.00, 0.03, 0.06) multiferroic ferrites was synthesized using the sol–gel method. To gain comprehensive insights into these materials, we employed a range of characterization techniques, including X-ray diffraction, Raman and Fourier transform infrared spectroscopies, field emission scanning electron microscopy, UV–Vis spectroscopy, and a vibrating sample magnetometer. Our analysis reveals a rhombohedral crystal structure (<em>R</em>3<em>c</em> space group) for the synthesized ferrites. Notably, we observe a substantial decrease in the optical band gap as the RE/Zr co-substitution increases. Further investigation into the magnetic properties shows a remarkable transition from antiferromagnetic to ferromagnetic behavior, which we attribute to the disruption of the long-range periodicity of the spin cycloid and 4f-3d orbital interactions. In addition, we tested the photocatalytic performance of the RE/Zr co-substituted BiFeO<sub>3</sub> nanoparticles for the degradation of methyl orange dye under sunlight. The results are quite impressive, with degradation efficiency reaching up to 100% at 40 min by the Bi<sub>1–<em>x</em></sub>RE<sub><em>x</em></sub>Fe<sub>1–<em>x</em></sub>Zr<sub><em>x</em></sub>O<sub>3</sub> (RE = La, Sm). Overall, our study demonstrates the vast potential of Bi<sub>1–<em>x</em></sub>RE<sub><em>x</em></sub>Fe<sub>1–<em>x</em></sub>Zr<sub><em>x</em></sub>O<sub>3</sub> ferrites in various fields, including optics, magnetism, water treatment, and environmental preservation.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 12","pages":"Pages 2654-2663"},"PeriodicalIF":7.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145594826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-16DOI: 10.1016/j.jre.2025.04.006
Tuğba Şaşmaz Kuru , Mehmet Kuru
Rare earth (RE) doped ferrites with the chemical formula Cu0.3Zn0.3Mg0.4TxFe2–xO4 (x = 0, 0.1; T = La, Ce, Sr) were synthesized by chemical co-precipitation method. The structural, optical, electrical and humidity sensing properties of Cu–Mg–Zn ferrites with rare earth element doping were investigated. Single-phase cubic spinel structure was confirmed via X-ray diffraction (XRD), and the crystal size ranges from 22.12 to 63.17 nm according to the Scherrer formula and from 25.66 to 67.46 nm according to the Williamson–Hall method. Porous structure and elemental characterization of the samples were investigated by scanning electron microscopy (SEM). The optic band gap varies between 2.21 and 2.49 eV. Electrical measurements were conducted in the frequency range of 1 Hz–20 MHz and temperature range of 25–400 °C. It has been determined that the dielectric results are consistent with the Maxwell–Wagner method and exhibit a non-Debye relaxation model, as observed from the Nyquist plots. At a minimum frequency value of 1 Hz, the dielectric constants for pure, Ce, Sr, and La samples are 9 × 104, 5 × 104, 1 × 108, and 2 × 105 at 25 °C, and 1.85 × 108, 1.34 × 108, 1.15 × 1010, and 4.4 × 108 at 400 °C. In the same order, for the maximum frequency value of 20 MHz, the dielectric constants at 25 °C are 169, 166, 3799, and 60, while at 400 °C they are 734, 624, 12108, and 774. The La doped sample's low dielectric loss makes it suitable for high-frequency applications. Humidity measurements were performed at room temperature and in the 5%–95% relative humidity range. The humidity properties of the samples were investigated through humidity mapping, sensitivity, hysteresis, and long-term stability tests. Compared to other samples, the results indicate that Ce exhibits better humidity performance with 99% sensitivity and the highest repeatability (91.2%). These results show that Ce-doped ferrite can be used as a low-cost, high-performance humidity sensor.
{"title":"Effect of rare earth doping on structural, optical, dielectric, and humidity properties of Cu–Mg–Zn ferrites","authors":"Tuğba Şaşmaz Kuru , Mehmet Kuru","doi":"10.1016/j.jre.2025.04.006","DOIUrl":"10.1016/j.jre.2025.04.006","url":null,"abstract":"<div><div>Rare earth (RE) doped ferrites with the chemical formula Cu<sub>0.3</sub>Zn<sub>0.3</sub>Mg<sub>0.4</sub>T<sub><em>x</em></sub>Fe<sub>2–<em>x</em></sub>O<sub>4</sub> (<em>x</em> = 0, 0.1; T = La, Ce, Sr) were synthesized by chemical co-precipitation method. The structural, optical, electrical and humidity sensing properties of Cu–Mg–Zn ferrites with rare earth element doping were investigated. Single-phase cubic spinel structure was confirmed via X-ray diffraction (XRD), and the crystal size ranges from 22.12 to 63.17 nm according to the Scherrer formula and from 25.66 to 67.46 nm according to the Williamson–Hall method. Porous structure and elemental characterization of the samples were investigated by scanning electron microscopy (SEM). The optic band gap varies between 2.21 and 2.49 eV. Electrical measurements were conducted in the frequency range of 1 Hz–20 MHz and temperature range of 25–400 °C. It has been determined that the dielectric results are consistent with the Maxwell–Wagner method and exhibit a non-Debye relaxation model, as observed from the Nyquist plots. At a minimum frequency value of 1 Hz, the dielectric constants for pure, Ce, Sr, and La samples are 9 × 10<sup>4</sup>, 5 × 10<sup>4</sup>, 1 × 10<sup>8</sup>, and 2 × 10<sup>5</sup> at 25 °C, and 1.85 × 10<sup>8</sup>, 1.34 × 10<sup>8</sup>, 1.15 × 10<sup>10</sup>, and 4.4 × 10<sup>8</sup> at 400 °C. In the same order, for the maximum frequency value of 20 MHz, the dielectric constants at 25 °C are 169, 166, 3799, and 60, while at 400 °C they are 734, 624, 12108, and 774. The La doped sample's low dielectric loss makes it suitable for high-frequency applications. Humidity measurements were performed at room temperature and in the 5%–95% relative humidity range. The humidity properties of the samples were investigated through humidity mapping, sensitivity, hysteresis, and long-term stability tests. Compared to other samples, the results indicate that Ce exhibits better humidity performance with 99% sensitivity and the highest repeatability (91.2%). These results show that Ce-doped ferrite can be used as a low-cost, high-performance humidity sensor.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 10","pages":"Pages 2257-2268"},"PeriodicalIF":7.2,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1016/j.jre.2025.03.026
Lihua Hu , Suning Zhang , Peishen Zhao , Jie Yang , Gongde Wu , Wei Xu
The catalytic direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol is a crucial approach to utilizing CO2 and producing high-value chemicals. However, the high stability of the CO2 molecule imposes thermodynamic limitations on this reaction pathway, along with challenges related to insufficient catalyst activity and stability. Currently, solutions primarily focus on developing efficient catalyst. Herein, La-doped CeO2 nanoflower catalysts (LaxCeO2) were synthesized via hydrothermal method. Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies, thereby enhancing catalytic performance. Notably, La0.1CeO2 exhibits the largest pore size and highest oxygen vacancy content, achieving a remarkable DMC productivity of 9.42 mmol/g under 140 °C, 4 MPa of CO2, and 3 h of reaction, surpassing pure CeO2 nanoflowers. Based on experimental findings and in-situ diffuse infrared Fourier transform analysis, a plausible reaction pathway was proposed. This work underscores the potential of LaxCeO2 nanoflowers as efficient catalysts for sustainable CO2 conversion to DMC.
{"title":"La-doped CeO2 nanoflowers catalysts for direct synthesis of dimethyl carbonate from CO2 and methanol","authors":"Lihua Hu , Suning Zhang , Peishen Zhao , Jie Yang , Gongde Wu , Wei Xu","doi":"10.1016/j.jre.2025.03.026","DOIUrl":"10.1016/j.jre.2025.03.026","url":null,"abstract":"<div><div>The catalytic direct synthesis of dimethyl carbonate (DMC) from CO<sub>2</sub> and methanol is a crucial approach to utilizing CO<sub>2</sub> and producing high-value chemicals. However, the high stability of the CO<sub>2</sub> molecule imposes thermodynamic limitations on this reaction pathway, along with challenges related to insufficient catalyst activity and stability. Currently, solutions primarily focus on developing efficient catalyst. Herein, La-doped CeO<sub>2</sub> nanoflower catalysts (La<sub><em>x</em></sub>CeO<sub>2</sub>) were synthesized via hydrothermal method. Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies, thereby enhancing catalytic performance. Notably, La<sub>0.1</sub>CeO<sub>2</sub> exhibits the largest pore size and highest oxygen vacancy content, achieving a remarkable DMC productivity of 9.42 mmol/g under 140 °C, 4 MPa of CO<sub>2</sub>, and 3 h of reaction, surpassing pure CeO<sub>2</sub> nanoflowers. Based on experimental findings and <em>in-situ</em> diffuse infrared Fourier transform analysis, a plausible reaction pathway was proposed. This work underscores the potential of La<sub><em>x</em></sub>CeO<sub>2</sub> nanoflowers as efficient catalysts for sustainable CO<sub>2</sub> conversion to DMC.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"43 10","pages":"Pages 2177-2185"},"PeriodicalIF":7.2,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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