Pub Date : 2026-01-01Epub Date: 2025-09-03DOI: 10.1016/j.jre.2025.09.003
Bárbara Da Rocha Pereira, Fernanda Fajardo Nacif Petraglia, Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenório
Rare earth elements (REEs) are utilized in various fields due to their unique properties, which are essential for developing new technologies. However, these elements have become critical due to supply restrictions. The search for new sources through recycling is emphasized to promote supply and foster a circular economy, thereby mitigating environmental impacts. Recovery processes through the extraction and purification of REEs from secondary sources, seeking alternatives to mining and aiming to reduce waste generation and energy consumption. The potential for REE recovery using techniques such as leaching, precipitation, ion exchange, and solvent extraction is also highlighted. The recovery and recycling of rare earth elements (REEs) represent an opportunity for sustainable development through waste treatment, promoting a circular economy.
{"title":"Hydrometallurgical innovations for recovery of rare earth elements from secondary sources: A comparative review","authors":"Bárbara Da Rocha Pereira, Fernanda Fajardo Nacif Petraglia, Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenório","doi":"10.1016/j.jre.2025.09.003","DOIUrl":"10.1016/j.jre.2025.09.003","url":null,"abstract":"<div><div>Rare earth elements (REEs) are utilized in various fields due to their unique properties, which are essential for developing new technologies. However, these elements have become critical due to supply restrictions. The search for new sources through recycling is emphasized to promote supply and foster a circular economy, thereby mitigating environmental impacts. Recovery processes through the extraction and purification of REEs from secondary sources, seeking alternatives to mining and aiming to reduce waste generation and energy consumption. The potential for REE recovery using techniques such as leaching, precipitation, ion exchange, and solvent extraction is also highlighted. The recovery and recycling of rare earth elements (REEs) represent an opportunity for sustainable development through waste treatment, promoting a circular economy.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 1-14"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941225","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 : 2026-01-01Epub Date: 2025-02-25DOI: 10.1016/j.jre.2025.02.012
Peidong Liu, Xu Wang, Wencai Zhang
Organic acids are increasingly recognized as an environmentally friendly and efficient selective leaching agent of critical minerals. However, their impact on subsequent extraction processes remains unclear. This study investigated the extraction behavior of rare earth elements (REEs), representative of critical minerals, in the presence of various organic acids, including citric acid, maleic acid, malonic acid, DL-malic acid, L(+)-tartaric acid, and L-ascorbic acid. Organic acids exhibit a slight inhibitory effect on REE extraction, while significantly enhancing the extraction of Al(III), thereby complicating REE separation. Therefore, the concentration of organic acids should be maintained as low as possible in practical applications. Under the optimized conditions, the inhibitory effects on REEs are negligible, and undesired Al extraction is minimized by adjusting contact time. The study identifies malonic and L(+)-tartaric acids as particularly effective for selective separation. Mechanistically, organic acids are likely to form complexes with REEs and D2EHPA during extraction, except for Y(III), offering practical guidelines for optimizing REE recovery. The recovery of organic acids can be achieved by precipitating REEs from stripping solutions using oxalic acid, adding further environmental and economic benefits. This study provides both theoretical insights and experimental evidence for the separation of REEs from aqueous containing organic acids, offering a valuable reference for the recovery of other critical minerals from such solutions.
{"title":"Impact of organic acids on extraction of rare earth elements: Mechanisms and optimization","authors":"Peidong Liu, Xu Wang, Wencai Zhang","doi":"10.1016/j.jre.2025.02.012","DOIUrl":"10.1016/j.jre.2025.02.012","url":null,"abstract":"<div><div>Organic acids are increasingly recognized as an environmentally friendly and efficient selective leaching agent of critical minerals. However, their impact on subsequent extraction processes remains unclear. This study investigated the extraction behavior of rare earth elements (REEs), representative of critical minerals, in the presence of various organic acids, including citric acid, maleic acid, malonic acid, DL-malic acid, L(+)-tartaric acid, and L-ascorbic acid. Organic acids exhibit a slight inhibitory effect on REE extraction, while significantly enhancing the extraction of Al(III), thereby complicating REE separation. Therefore, the concentration of organic acids should be maintained as low as possible in practical applications. Under the optimized conditions, the inhibitory effects on REEs are negligible, and undesired Al extraction is minimized by adjusting contact time. The study identifies malonic and L(+)-tartaric acids as particularly effective for selective separation. Mechanistically, organic acids are likely to form complexes with REEs and D2EHPA during extraction, except for Y(III), offering practical guidelines for optimizing REE recovery. The recovery of organic acids can be achieved by precipitating REEs from stripping solutions using oxalic acid, adding further environmental and economic benefits. This study provides both theoretical insights and experimental evidence for the separation of REEs from aqueous containing organic acids, offering a valuable reference for the recovery of other critical minerals from such solutions.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 299-310"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941398","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 : 2026-01-01Epub Date: 2024-12-14DOI: 10.1016/j.jre.2024.12.011
Kai Ma , Jingfeng Wang , Liqing Wang , Dongdong Zhang , Kui Wang
In this study, the Mg-Gd-Ni-Zn alloy containing Ni-LPSO was designed and prepared. Regulating the preheating temperature (430 °C/450 °C) before extrusion leads to the formation of dense lamellar γ′ phase, and the influence of γ′ phase on the recrystallisation behavior as well as the microstructure and its effect on the ageing behavior was investigated. The result shows that the higher preheating temperature increases the density of γ′ phase, which inhibits the dynamic recrystallisation (DRXed) process during hot extrusion. In addition, the γ′ phase in the deformed grains of EX450 alloy consumes solute atoms, resulting in a reduced aging strengthening effect compared to EX430 alloy. Due to the complete DRXed of EX430 alloy, the γ′ phase precipitated during the heat treatment process dissolves, increasing the concentration of solute atoms in the Mg matrix. This results in a significant precipitation strengthening effect in Ag430 alloy, and thus the mechanical properties of Ag430 alloy are higher than those of Ag450 alloy. In addition, immersion at 93 °C in 3 wt% KCl solution reduces the impediment to corrosion expansion by the uniform and complete corrosion products on the alloy surface as a result of γ′ phase compared to Ag450 alloy, which results in higher degradation properties of Ag430 alloy than those of Ag450 alloy. The Ag430 alloy exhibits the optimum comprehensive performance, with ultimate tensile strength (UTS) of 486 MPa, tensile yield strength (TYS) of 361 MPa, elongation (EL) of 13.1%, and degradation rate of 104.2 mg/(cm2·h) at 93 °C in 3 wt% KCl solution.
{"title":"Achieving high strength and high degradation of Mg-Gd-Ni-Zn alloy by LPSO and nano-precipitation phase","authors":"Kai Ma , Jingfeng Wang , Liqing Wang , Dongdong Zhang , Kui Wang","doi":"10.1016/j.jre.2024.12.011","DOIUrl":"10.1016/j.jre.2024.12.011","url":null,"abstract":"<div><div>In this study, the Mg-Gd-Ni-Zn alloy containing Ni-LPSO was designed and prepared. Regulating the preheating temperature (430 °C/450 °C) before extrusion leads to the formation of dense lamellar γ′ phase, and the influence of γ′ phase on the recrystallisation behavior as well as the microstructure and its effect on the ageing behavior was investigated. The result shows that the higher preheating temperature increases the density of γ′ phase, which inhibits the dynamic recrystallisation (DRXed) process during hot extrusion. In addition, the γ′ phase in the deformed grains of EX450 alloy consumes solute atoms, resulting in a reduced aging strengthening effect compared to EX430 alloy. Due to the complete DRXed of EX430 alloy, the γ′ phase precipitated during the heat treatment process dissolves, increasing the concentration of solute atoms in the Mg matrix. This results in a significant precipitation strengthening effect in Ag430 alloy, and thus the mechanical properties of Ag430 alloy are higher than those of Ag450 alloy. In addition, immersion at 93 °C in 3 wt% KCl solution reduces the impediment to corrosion expansion by the uniform and complete corrosion products on the alloy surface as a result of γ′ phase compared to Ag450 alloy, which results in higher degradation properties of Ag430 alloy than those of Ag450 alloy. The Ag430 alloy exhibits the optimum comprehensive performance, with ultimate tensile strength (UTS) of 486 MPa, tensile yield strength (TYS) of 361 MPa, elongation (EL) of 13.1%, and degradation rate of 104.2 mg/(cm<sup>2</sup>·h) at 93 °C in 3 wt% KCl solution.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 337-351"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941404","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 : 2026-01-01Epub Date: 2025-02-25DOI: 10.1016/j.jre.2025.02.016
Seonghun Choi , Sangwon Wi , Nguyen Duc Ton , Hongjoo Kim , Yunsang Lee
In this study, we investigated novel luminescence properties of GdTaO4, a material with high density and high effective atomic number, doped singly and triply with Eu3+, Er3+, and Tm3+ (GTO:RE, RE = Eu, Er, and Tm). Single-doped samples, GTO:Eu, GTO:Er, and GTO:Tm, exhibit distinct red, green, and blue color emissions with high purity, respectively. For the triple-doped samples, we obtain a high tunability of emission color depending on the excitation wavelength. The emission hue changes in the order of blue-purple-cyan-white-yellow-green-magenta with the increase in the excitation wavelength in the near-ultraviolet (NUV) range. Furthermore, we observe a significant X-ray-excited luminescence for GTO:RE. Our findings suggest that GTO:RE can be a multimodal phosphor providing versatile luminescence properties, such as the colorful emission hue change and dual excitation luminescence under both NUV and X-ray excitations.
在这项研究中，我们研究了一种高密度和高有效原子序数的材料GdTaO4， Eu3+， Er3+和Tm3+ （GTO:RE, RE = Eu, Er，和Tm）的单和三重掺杂。单掺杂样品GTO:Eu、GTO:Er和GTO:Tm分别表现出明显的红色、绿色和蓝色发射，纯度高。对于三掺杂样品，我们获得了发射颜色随激发波长的高可调性。在近紫外（NUV）范围内，随着激发波长的增加，发射色相呈蓝紫色-青色-白色-黄色-绿色-品红的顺序变化。此外，我们还观察到GTO:RE具有明显的x射线激发发光。我们的研究结果表明，GTO:RE可以成为一种多模态荧光体，具有多种发光特性，如在NUV和x射线激发下的彩色发射色调变化和双激发发光。
{"title":"Hue-changing luminescence and near-ultraviolet/X-ray dual excitation properties of GdTaO4 multi-doped with Eu3+, Er3+ and Tm3+","authors":"Seonghun Choi , Sangwon Wi , Nguyen Duc Ton , Hongjoo Kim , Yunsang Lee","doi":"10.1016/j.jre.2025.02.016","DOIUrl":"10.1016/j.jre.2025.02.016","url":null,"abstract":"<div><div>In this study, we investigated novel luminescence properties of GdTaO<sub>4</sub>, a material with high density and high effective atomic number, doped singly and triply with Eu<sup>3+</sup>, Er<sup>3+</sup>, and Tm<sup>3+</sup> (GTO:RE, RE = Eu, Er, and Tm). Single-doped samples, GTO:Eu, GTO:Er, and GTO:Tm, exhibit distinct red, green, and blue color emissions with high purity, respectively. For the triple-doped samples, we obtain a high tunability of emission color depending on the excitation wavelength. The emission hue changes in the order of blue-purple-cyan-white-yellow-green-magenta with the increase in the excitation wavelength in the near-ultraviolet (NUV) range. Furthermore, we observe a significant X-ray-excited luminescence for GTO:RE. Our findings suggest that GTO:RE can be a multimodal phosphor providing versatile luminescence properties, such as the colorful emission hue change and dual excitation luminescence under both NUV and X-ray excitations.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 47-55"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941536","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 : 2026-01-01Epub Date: 2025-03-25DOI: 10.1016/j.jre.2025.03.027
Liangchun Wei , Xiuling Liu , He Tang , Xiaoyun Mi , Meng Zhang , Ting Song , Liping Lu
A series of zero-thermal-quenching green-emitting phosphors Lu3−xAl5−yO12: Tb3+x, Sc3+y was developed. Upon the 272 nm excitation, two dominant emission bands centered at 488 and 543 nm are observed, which originate from the 5D4 → 7F6 and 5D4 → 7F5 transitions of Tb3+. In the singly Tb3+-doped samples, the luminous intensity increases evidently by increasing the Tb3+ concentration and reaching the maximum values when x = 0.09. It is proved that concentration quenching occurs mainly through the electric dipole–dipole interaction. The Sc3+ ion substitution strategy further enhances the emission intensity of Tb3+, and the quantum efficiency reaches 83.83%. The theoretical calculation results show that Sc3+ ions prefer to occupying Al3+ sites and cause lattice shrinkage, which increases the probability of Tb3+ transitions. Impressively, the phosphors exhibit zero-thermal-quenching luminescence at 478 K. Furthermore, the fluorescent latent fingerprint images developed by Lu2.91Al4.95O12: Tb3+0.09, Sc3+0.05 phosphors are well visualized. These results suggest that Lu2.91Al4.95O12: Tb3+0.09, Sc3+0.05 phosphors have significant potential for the application of latent fingerprints and solar blind UV detection.
{"title":"A zero-thermal-quenching green-emitting phosphor Lu3Al5O12: Tb3+, Sc3+ with high quantum efficiency for fingerprinting","authors":"Liangchun Wei , Xiuling Liu , He Tang , Xiaoyun Mi , Meng Zhang , Ting Song , Liping Lu","doi":"10.1016/j.jre.2025.03.027","DOIUrl":"10.1016/j.jre.2025.03.027","url":null,"abstract":"<div><div>A series of zero-thermal-quenching green-emitting phosphors Lu<sub>3−<em>x</em></sub>Al<sub>5−<em>y</em></sub>O<sub>12</sub>: Tb<sup>3+</sup><sub><em>x</em></sub>, Sc<sup>3+</sup><sub><em>y</em></sub> was developed. Upon the 272 nm excitation, two dominant emission bands centered at 488 and 543 nm are observed, which originate from the <sup>5</sup>D<sub>4</sub> → <sup>7</sup>F<sub>6</sub> and <sup>5</sup>D<sub>4</sub> → <sup>7</sup>F<sub>5</sub> transitions of Tb<sup>3+</sup>. In the singly Tb<sup>3+</sup>-doped samples, the luminous intensity increases evidently by increasing the Tb<sup>3+</sup> concentration and reaching the maximum values when <em>x</em> = 0.09. It is proved that concentration quenching occurs mainly through the electric dipole–dipole interaction. The Sc<sup>3+</sup> ion substitution strategy further enhances the emission intensity of Tb<sup>3+</sup>, and the quantum efficiency reaches 83.83%. The theoretical calculation results show that Sc<sup>3+</sup> ions prefer to occupying Al<sup>3+</sup> sites and cause lattice shrinkage, which increases the probability of Tb<sup>3+</sup> transitions. Impressively, the phosphors exhibit zero-thermal-quenching luminescence at 478 K. Furthermore, the fluorescent latent fingerprint images developed by Lu<sub>2.91</sub>Al<sub>4.95</sub>O<sub>12</sub>: Tb<sup>3+</sup><sub>0.09</sub>, Sc<sup>3+</sup><sub>0.05</sub> phosphors are well visualized. These results suggest that Lu<sub>2.91</sub>Al<sub>4.95</sub>O<sub>12</sub>: Tb<sup>3+</sup><sub>0.09</sub>, Sc<sup>3+</sup><sub>0.05</sub> phosphors have significant potential for the application of latent fingerprints and solar blind UV detection.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 94-102"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941503","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 : 2026-01-01Epub Date: 2025-02-25DOI: 10.1016/j.jre.2025.02.014
Kanwal Iqbal , Anam Iqbal , Kalsoom Abdul Haq , Saqiba Tahir , Imran Khan , Sara Benabid
The discharge of organic pollutants, particularly dyes, into aquatic environments is a serious environmental risk. The AlPO4-5@Ce/Mg-Al LDH hybrid catalyst facilitates NaBH4-mediated reduction by promoting electron transfer from NaBH4 to the dye molecules, which accelerates the degradation of dyes. The synergistic interaction between the Ce/Mg-Al LDH and AlPO4-5 components enhances this catalytic efficiency. The catalyst likely enhances the reduction process by creating an environment that activates NaBH4 more effectively; however, the agglomeration of catalysts, such as 2D zeolites (AlPO4-5), limits their effectiveness. Agglomeration restricts access to active sites, reducing catalytic efficiency. In this study, the combination of exfoliated Ce-doped layered double hydroxides with AlPO4-5 prevents agglomeration by ensuring nanoscale mixing, which increases the available surface area and improves contact between the catalyst and the reactants. The versatility of Ce-doped layered double hydroxides (Ce/Mg-Al LDH), along with their function as precursors and substrates, has attracted interest, as they provide metal sources and anchoring sites for catalyst nucleation. This study presents a novel AlPO4-5@Ce/Mg-Al LDH hybrid catalyst synthesized via solvothermal synthesis and in-situ self-assembly. It is found that the combination of AlPO4-5 and exfoliated Ce/Mg-Al LDH prevents catalyst agglomeration and ensures nanoscale mixing. AlPO4-5 is uniformly anchored on the Ce/Mg-Al LDH surface, forming a hybrid nanostructure. Catalytic activity was assessed using the model dye methyl orange (MO), showing superior performance with a rate constant (kapp) of 0.03 s−1. The enhanced activity is attributed to the synergistic interaction between AlPO4-5 and Ce/Mg-Al LDH, with the latter acting as a co-catalyst. Furthermore, the hybrid catalyst retains its activity after five reuse cycles. This work demonstrates the potential of AlPO4-5@Ce/Mg-Al LDH as an efficient, reusable nanocatalyst with controlled composition and consistent structure for water pollutant degradation.
{"title":"Efficient discoloration of organic dye pollutants from Hanna Lake water, Balochistan, using hybrid 2D AlPO4-5@Ce/Mg-Al LDH nanocatalyst","authors":"Kanwal Iqbal , Anam Iqbal , Kalsoom Abdul Haq , Saqiba Tahir , Imran Khan , Sara Benabid","doi":"10.1016/j.jre.2025.02.014","DOIUrl":"10.1016/j.jre.2025.02.014","url":null,"abstract":"<div><div>The discharge of organic pollutants, particularly dyes, into aquatic environments is a serious environmental risk. The AlPO<sub>4</sub>-5@Ce/Mg-Al LDH hybrid catalyst facilitates NaBH<sub>4</sub>-mediated reduction by promoting electron transfer from NaBH<sub>4</sub> to the dye molecules, which accelerates the degradation of dyes. The synergistic interaction between the Ce/Mg-Al LDH and AlPO<sub>4</sub>-5 components enhances this catalytic efficiency. The catalyst likely enhances the reduction process by creating an environment that activates NaBH<sub>4</sub> more effectively; however, the agglomeration of catalysts, such as 2D zeolites (AlPO<sub>4</sub>-5), limits their effectiveness. Agglomeration restricts access to active sites, reducing catalytic efficiency. In this study, the combination of exfoliated Ce-doped layered double hydroxides with AlPO<sub>4</sub>-5 prevents agglomeration by ensuring nanoscale mixing, which increases the available surface area and improves contact between the catalyst and the reactants. The versatility of Ce-doped layered double hydroxides (Ce/Mg-Al LDH), along with their function as precursors and substrates, has attracted interest, as they provide metal sources and anchoring sites for catalyst nucleation. This study presents a novel AlPO<sub>4</sub>-5@Ce/Mg-Al LDH hybrid catalyst synthesized via solvothermal synthesis and <em>in-situ</em> self-assembly. It is found that the combination of AlPO<sub>4</sub>-5 and exfoliated Ce/Mg-Al LDH prevents catalyst agglomeration and ensures nanoscale mixing. AlPO<sub>4</sub>-5 is uniformly anchored on the Ce/Mg-Al LDH surface, forming a hybrid nanostructure. Catalytic activity was assessed using the model dye methyl orange (MO), showing superior performance with a rate constant (<em>k</em><sub>app</sub>) of 0.03 s<sup>−1</sup>. The enhanced activity is attributed to the synergistic interaction between AlPO<sub>4</sub>-5 and Ce/Mg-Al LDH, with the latter acting as a co-catalyst. Furthermore, the hybrid catalyst retains its activity after five reuse cycles. This work demonstrates the potential of AlPO<sub>4</sub>-5@Ce/Mg-Al LDH as an efficient, reusable nanocatalyst with controlled composition and consistent structure for water pollutant degradation.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 205-212"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941482","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 : 2026-01-01Epub Date: 2025-02-28DOI: 10.1016/j.jre.2025.02.026
Weixin Liu, Yaping Wang, Li Cai, Jianping Zhang, Weixiao Ji, Ping Li, Changwen Zhang, Shengshi Li, Shishen Yan
The recently discovered ferrovalley materials have opened up new opportunities for exploiting novel valleytronic devices capable of storing and processing information. For energy-efficient device applications, achieving electrically controllable valley polarization in ferrovalley materials is of paramount importance. However, most ferrovalley materials inherently lack electrical controllability over valley polarization. Herein, based on first-principles calculations, we demonstrate that the valley polarization of the GdCl2 bilayer can be effectively manipulated through electrical means with the aid of the layer degree of freedom. The GdCl2 bilayer exhibits a magnetic ground state that is dependent on the stacking pattern, with ferromagnetic and antiferromagnetic couplings observed in the AA and AB patterns, respectively. Interestingly, the AA bilayer successfully realizes the coexistence of spontaneous ferroelectric polarization and spin-polarized valley polarization. By switching the electric polarization, the layer contribution of valley polarization will be reversed correspondingly, thus enabling different GdCl2 monolayers to selectively generate the anomalous valley Hall effect (AVHE). Besides, the band splitting can be significantly enhanced by varying the interlayer distance, which makes the generation and manipulation of AVHE more robust. In the AB bilayer without ferroelectricity, the application of a perpendicular electric field can induce spin splitting in energy bands, and flipping the direction of the electric field also allows for flexible control over layer-dependent valley polarization and AVHE. Moreover, two conceptual electrically writable and readable memory devices are proposed based on these two types of stacked GdCl2 bilayer. This study paves the way for the utilization of ferrovalley bilayer in advancing high-performance valleytronic devices.
{"title":"Electrically controlled valley polarization and anomalous valley Hall effect in GdCl2 bilayer","authors":"Weixin Liu, Yaping Wang, Li Cai, Jianping Zhang, Weixiao Ji, Ping Li, Changwen Zhang, Shengshi Li, Shishen Yan","doi":"10.1016/j.jre.2025.02.026","DOIUrl":"10.1016/j.jre.2025.02.026","url":null,"abstract":"<div><div>The recently discovered ferrovalley materials have opened up new opportunities for exploiting novel valleytronic devices capable of storing and processing information. For energy-efficient device applications, achieving electrically controllable valley polarization in ferrovalley materials is of paramount importance. However, most ferrovalley materials inherently lack electrical controllability over valley polarization. Herein, based on first-principles calculations, we demonstrate that the valley polarization of the GdCl<sub>2</sub> bilayer can be effectively manipulated through electrical means with the aid of the layer degree of freedom. The GdCl<sub>2</sub> bilayer exhibits a magnetic ground state that is dependent on the stacking pattern, with ferromagnetic and antiferromagnetic couplings observed in the AA and AB patterns, respectively. Interestingly, the AA bilayer successfully realizes the coexistence of spontaneous ferroelectric polarization and spin-polarized valley polarization. By switching the electric polarization, the layer contribution of valley polarization will be reversed correspondingly, thus enabling different GdCl<sub>2</sub> monolayers to selectively generate the anomalous valley Hall effect (AVHE). Besides, the band splitting can be significantly enhanced by varying the interlayer distance, which makes the generation and manipulation of AVHE more robust. In the AB bilayer without ferroelectricity, the application of a perpendicular electric field can induce spin splitting in energy bands, and flipping the direction of the electric field also allows for flexible control over layer-dependent valley polarization and AVHE. Moreover, two conceptual electrically writable and readable memory devices are proposed based on these two types of stacked GdCl<sub>2</sub> bilayer. This study paves the way for the utilization of ferrovalley bilayer in advancing high-performance valleytronic devices.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 281-289"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941490","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}
Lanthanide rare earth elements (Ln), particularly cerium (Ce) and its compounds, have attracted widespread attention for their role in modulating the local coordination environment of active sites in hosts, thereby the enhanced performance of oxygen evolution reactions (OER). However, there has been limited research on the influence of Ce compounds with the particle size of clusters or smaller on the kinetics performance of hydrolysis of the host. In this work, chemical vapor deposition (CVD) planted NiSx/C3N4 heterostructure nanoarrays, modified surface with the CeO2 clusters (CeO2@NiSx/C3N4) is reported and exhibits a superior OER activity. At the current density of 10 mA/cm2, the overpotential of the optimized CeO2@NiSx/C3N4 is as low as 46 mV, and only 247 mV is required to reach a current density of 100 mA/cm2, significantly lower than that of NiSx/C3N4 (349 mV). Density functional theory (DFT) calculations confirm that the loaded CeO2 clusters efficaciously modify the differential charge density distribution of the adjacent active sites and optimized the Gibbs free energy (ΔG) between the active sites and the hydrolysis intermediates, thus enhancing the OER performance of CeO2@NiSx/C3N4. This work provides a reference for the design and preparation of Ln compounds modified electrodes applied in the field of electrochemical energy conversion and storage and the investigation of the involved mechanisms.
{"title":"Cerium oxide cluster modified nickel sulfide/carbon nitride heterostructure for efficient oxygen evolution reaction","authors":"Kexin Sun, Qiang Han, Sicheng Cui, Yuxi Chen, Liqi Wang, Mingzhi Hu, Zexin Li, Qi Zhang, Jihui Lang","doi":"10.1016/j.jre.2025.03.024","DOIUrl":"10.1016/j.jre.2025.03.024","url":null,"abstract":"<div><div>Lanthanide rare earth elements (Ln), particularly cerium (Ce) and its compounds, have attracted widespread attention for their role in modulating the local coordination environment of active sites in hosts, thereby the enhanced performance of oxygen evolution reactions (OER). However, there has been limited research on the influence of Ce compounds with the particle size of clusters or smaller on the kinetics performance of hydrolysis of the host. In this work, chemical vapor deposition (CVD) planted NiS<sub><em>x</em></sub>/C<sub>3</sub>N<sub>4</sub> heterostructure nanoarrays, modified surface with the CeO<sub>2</sub> clusters (CeO<sub>2</sub>@NiS<sub><em>x</em></sub>/C<sub>3</sub>N<sub>4</sub>) is reported and exhibits a superior OER activity. At the current density of 10 mA/cm<sup>2</sup>, the overpotential of the optimized CeO<sub>2</sub>@NiS<sub><em>x</em></sub>/C<sub>3</sub>N<sub>4</sub> is as low as 46 mV, and only 247 mV is required to reach a current density of 100 mA/cm<sup>2</sup>, significantly lower than that of NiS<sub><em>x</em></sub>/C<sub>3</sub>N<sub>4</sub> (349 mV). Density functional theory (DFT) calculations confirm that the loaded CeO<sub>2</sub> clusters efficaciously modify the differential charge density distribution of the adjacent active sites and optimized the Gibbs free energy (Δ<em>G</em>) between the active sites and the hydrolysis intermediates, thus enhancing the OER performance of CeO<sub>2</sub>@NiS<sub><em>x</em></sub>/C<sub>3</sub>N<sub>4</sub>. This work provides a reference for the design and preparation of Ln compounds modified electrodes applied in the field of electrochemical energy conversion and storage and the investigation of the involved mechanisms.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 129-136"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941507","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 : 2026-01-01Epub Date: 2024-12-12DOI: 10.1016/j.jre.2024.12.009
Amna Muneer , Muhammad Imran Arshad , Mudasar Nazir , Nasir Amin , Kiran Mehmood , Maria Akhtar , Kashif Javaid , Sadia Ata , Ammara Aslam , Lamia Ben Farhat , Faisal Alresheedi , Zohaib Hassan Nawaz , Muhammad Tariq Sajjad
This study explored the effect of graphene nanoplatelets (GNPs) doping on the magnetic and photocatalytic properties of Ni0.5Co0.25Mg0.25Ho0.03Fe1.97O4 ferrite (NCMHF)/GNPs composites. XRD analysis reveals the presence of single-phase structures and a reduction in crystallite size from 28.06 to 20.17 nm with the incorporation of GNPs. Raman analysis confirms the ferrite spinel structure along with the G and D bands, indicating the successful integration of GNPs in the composites. SEM micrographs show reduced agglomeration with the addition of GNPs. A reciprocal relationship between the lattice parameter (a) and bandgap energy () is observed. Among the studied composites, the NCMHF/1.25 wt% GNPs exhibits an of 2.14 eV and a temperature coefficient of resistance (TCR) of −6.59%/K. This composite also achieves a higher permeability and magnetic quality factor (Q) with Q reaching 851 at 5.5 MHz. Meanwhile, the NCMHF/2.25 wt% GNPs composite demonstrate remarkable photodegradation efficiency for Direct Red 23 dye, achieving 88% degradation. The outstanding electromagnetic properties of the NCMHF-GNPs composites make them well-suited for high frequency applications, microwave shielding, high-density data storage, magnetic and bolometric devices. Additionally, their photodegradition performance provides a cost-effective and sustainable solution for water purification.
{"title":"Engineering Ni0.5Co0.25Mg0.25Ho0.03Fe1.97O4 ferrite-grafted graphene nanoplatelets (GNPs) composites for rapid degradation of Direct Red 23 dye (DRD-23)","authors":"Amna Muneer , Muhammad Imran Arshad , Mudasar Nazir , Nasir Amin , Kiran Mehmood , Maria Akhtar , Kashif Javaid , Sadia Ata , Ammara Aslam , Lamia Ben Farhat , Faisal Alresheedi , Zohaib Hassan Nawaz , Muhammad Tariq Sajjad","doi":"10.1016/j.jre.2024.12.009","DOIUrl":"10.1016/j.jre.2024.12.009","url":null,"abstract":"<div><div>This study explored the effect of graphene nanoplatelets (GNPs) doping on the magnetic and photocatalytic properties of Ni<sub>0.5</sub>Co<sub>0.25</sub>Mg<sub>0.25</sub>Ho<sub>0.03</sub>Fe<sub>1.97</sub>O<sub>4</sub> ferrite (NCMHF)/GNPs composites. XRD analysis reveals the presence of single-phase structures and a reduction in crystallite size from 28.06 to 20.17 nm with the incorporation of GNPs. Raman analysis confirms the ferrite spinel structure along with the G and D bands, indicating the successful integration of GNPs in the composites. SEM micrographs show reduced agglomeration with the addition of GNPs. A reciprocal relationship between the lattice parameter (<em>a</em>) and bandgap energy (<span><math><mrow><msub><mi>E</mi><mi>g</mi></msub></mrow></math></span>) is observed. Among the studied composites, the NCMHF/1.25 wt% GNPs exhibits an <span><math><mrow><msub><mi>E</mi><mi>g</mi></msub></mrow></math></span> of 2.14 eV and a temperature coefficient of resistance (TCR) of −6.59%/K. This composite also achieves a higher permeability <span><math><mrow><msup><mi>μ</mi><mo>′</mo></msup></mrow></math></span> and magnetic quality factor (<em>Q</em>) with <em>Q</em> reaching 851 at 5.5 MHz. Meanwhile, the NCMHF/2.25 wt% GNPs composite demonstrate remarkable photodegradation efficiency for Direct Red 23 dye, achieving 88% degradation. The outstanding electromagnetic properties of the NCMHF-GNPs composites make them well-suited for high frequency applications, microwave shielding, high-density data storage, magnetic and bolometric devices. Additionally, their photodegradition performance provides a cost-effective and sustainable solution for water purification.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 151-161"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941509","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 : 2026-01-01Epub Date: 2025-03-04DOI: 10.1016/j.jre.2025.03.002
Jiangbo Yu , Jing Yu , Dihong Zhang , Kaige Xu , Kaiyin Qiu , Jie Liu , Zhanchao Wu , Haoen Lu , Ruoxin Xuan , Yuhan Xiong , Shaoping Kuang
Incorporating rare-earth element into semiconductors has been regarded as an effective method to improve the photocatalytic activity for degradation of pollutants in water. In this paper, Ce-ZnO/CH (Ce-ZnO/chitosan) composites were prepared by one-step solution for degradation of Rhodamine B (RhB). The photocatalytic performance is improved by 3.5 times through doping Ce to ZnO/CH and the degradation rate of RhB can reach 100 mol% within 40 min. This is attributed to the combined effect of Ce and chitosan on the prepared photocatalytic composite. Firstly, the addition of chitosan enhances the photocatalytic composite's adsorption performance for RhB and effectively prevents the aggregation of ZnO particles. Secondly, the doping of Ce reduces the bandgap energy of ZnO and enhances its response to visible light. Thirdly, the addition of Ce forms electron capture traps, which hinder the recombination of e–-h+ pairs. It is believed that hydroxyl radicals (·OH) and superoxide radicals (·O2–) play the main role. Also, this material shows excellent regeneration performance. These results indicates that Ce-ZnO/CH composites have a promising commercial application prospect in dye wastewater treatment.
{"title":"Cerium and chitosan co-modified ZnO composites for enhancing visible light photocatalytic degradation of Rhodamine B","authors":"Jiangbo Yu , Jing Yu , Dihong Zhang , Kaige Xu , Kaiyin Qiu , Jie Liu , Zhanchao Wu , Haoen Lu , Ruoxin Xuan , Yuhan Xiong , Shaoping Kuang","doi":"10.1016/j.jre.2025.03.002","DOIUrl":"10.1016/j.jre.2025.03.002","url":null,"abstract":"<div><div>Incorporating rare-earth element into semiconductors has been regarded as an effective method to improve the photocatalytic activity for degradation of pollutants in water. In this paper, Ce-ZnO/CH (Ce-ZnO/chitosan) composites were prepared by one-step solution for degradation of Rhodamine B (RhB). The photocatalytic performance is improved by 3.5 times through doping Ce to ZnO/CH and the degradation rate of RhB can reach 100 mol% within 40 min. This is attributed to the combined effect of Ce and chitosan on the prepared photocatalytic composite. Firstly, the addition of chitosan enhances the photocatalytic composite's adsorption performance for RhB and effectively prevents the aggregation of ZnO particles. Secondly, the doping of Ce reduces the bandgap energy of ZnO and enhances its response to visible light. Thirdly, the addition of Ce forms electron capture traps, which hinder the recombination of e<sup>–</sup>-h<sup>+</sup> pairs. It is believed that hydroxyl radicals (·OH) and superoxide radicals (·O<sub>2</sub><sup>–</sup>) play the main role. Also, this material shows excellent regeneration performance. These results indicates that Ce-ZnO/CH composites have a promising commercial application prospect in dye wastewater treatment.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 1","pages":"Pages 196-204"},"PeriodicalIF":7.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941510","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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