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Effectively enhanced photoluminescence of CePO_(4):Tb^(3+)nanorods combined with carbon dots

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Journal of rare earths 2022年第7期40卷 1007-1013页

作者： Yanyan Wang Dan Yue Boshi Tian Weidong Li Bing Zhang Liu Yang Yue Li Zhenling Wang Yilei Zhang Henan International Joint Laboratory of rare earth Composite materials College of Materials EngineeringHenan Key Laboratory of Electronic Ceramic Materials and ApplicationHenan University of EngineeringXinzheng 451191China College of Chemistry Zhengzhou UniversityZhengzhou 450001China Henan Key Laboratory of rare earth functional materials Zhoukou Normal UniversityZhoukou 466001China Civil&Mechanical engineering University of CanterburyChristchurch8140New Zealand

CePO_(4):Tb^(3+)nanorods were successfully obtained via a simple hydrothermal method and combined with carbon dots(CDs)to obtain CDs@CePO_(4):Tb^(3+)*** to the combination of CDs,the emission intensity of CDs@CePO_(4):Tb^(3+)nanorods increases about 92 times,compared with that of CePO_(4):Tb^(3+)*** combination of CDs and CePO_(4):Tb^(3+)nanorods was confirmed by Fourier transform infrared spectroscopy(FTIR),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)and so *** mechanism of luminescence enhancement may be attributed to some aspects:the formation of hexagonal phase results in the increase of crystal field symmetry,and the energy transfer among CDs,Ce^(3+)and Tb^(3+)ions,which causes the Tb^(3+)ions in CDs@CePO_(4):Tb^(3+)nano rods to obtain mo re excited energy and less non-radiative atte nuation co mpared to CePO_(4):Tb^(3+)nano *** luminescence enhancement strategy through combination of CDs would provide a simple and effective approach for other rare earth ions doped luminescent materials.

关键词： CePO_(4) rare earth ions Doping Carbon dots Photoluminescence enhancement

Non-bonding modulations between single atomic cerium and monodispersed selenium sites towards efficient oxygen reduction

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Nano research 2024年第6期17卷 4753-4763页

作者： Leilei Yin Shuai Zhang Mingzi Sun Siyuan Wang Bolong Huang Yaping Du Tianjin Key Lab for rare earth materials and Applications Center for Rare Earth and Inorganic Functional MaterialsHaihe Laboratory of Sustainable Chemical TransformationsSmart Sensing Interdisciplinary Science CenterSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjin 300350China Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic UniversityHung HomKowloon 999077Hong KongChina research centre for Carbon-Strategic Catalysis The Hong Kong Polytechnic UniversityHung HomKowloon 999077Hong KongChina

Currently,dual atomic catalysts(DACs)with neighboring active sites for oxygen reduction reaction(ORR)still meet lots of challenges in the synthesis,especially the construction of atomic pairs of elements from different blocks of the periodic ***,a“rare earth(Ce)-metalloid(Se)”non-bonding heteronuclear diatomic electrocatalyst has been constructed for ORR by rational coordination and carbon support defect ***,the optimized Ce-Se diatomic catalysts(Ce-Se DAs/NC)displayed a half-wave potential of 0.886 V *** hydrogen electrode(RHE)and excellent stability,which surpass those of separate Ce or Se single atoms and most single/dual atomic catalysts ever *** addition,a primary zinc-air battery constructed using Ce-Se DAs/NC delivers a higher peak power density(209.2 mW·cm^(−2))and specific capacity(786.4 mAh·gZn^(−1))than state-of-the-art noble metal catalysts Pt/*** calculations reveal that the Ce-Se DAs/NC has improved the electroactivity of the Ce-N_(4)region due to the electron transfer towards the nearby Se specific activity(SA)***,the more electron-rich Se sites promote the adsorptions of key intermediates,which results in the optimal performances of ORR on Ce-Se DAs/*** work provides new perspectives on electronic structure modulations via non-bonded long-range coordination micro-environment engineering in DACs for efficient electrocatalysis.

关键词： catalyst rare earth oxygen reduction reaction(ORR) metalloid non-bonding modulation

Coercivity enhancement mechanism of Tb-diffusion Nd-Fe-B sintered magnets studied by magneto-optical Kerr optical microscope

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rare Metals 2021年第3期40卷 570-574页

作者： Dan Wu Wei-Qiang Liu Ming Yue Qiong Wu Dong-Tao Zhang Qing-Mei Lu Xu-Liang Li Jing-Wu Chen Key Laboratory of Advanced functional materials College of Materials Science and EngineeringBeijing University of TechnologyMinistry of Education of ChinaBeijing 100124China State Key Laboratory of rare earth Permanent Magnetic materials Hefei 231500China

The coercivity,microstructure,and magnetic domain structure of Nd-Fe-B sintered magnets by grain boundary diffusion process(GBDP) with TbH3 nanoparticles were systematically *** to the original magnet,the coercivity(Hci) of the GBDP magnets improved from 1702 to 2374 kA·m^(-1) with few remanence reduced from 1.338 to 1.281 *** probe microanalysis(EPMA) analysis showed that Tb diffused along grain boundary,mainly concentrated in the boundary layer of the main phase,and formed a core-shell ***-optical Kerr optical microscope(MOKE) analysis showed that there were two types of magnetic domain reversal in one grain:gradual reversal(GR) and abrupt reversal(AR).When the applied field decreased from saturated magnetic field,the reversal magnetic domain nucleated and then spread over the whole grain gradually,which was called ***,some grains kept the single domain state until Hh which was a value of reverse direction applied field in second quadrant in hysteresis *** the applied field increased above Hh,reversed magnetic domain would suddenly appear and occupy most of the area of the grain,which was called *** is because AR grains have higher reversed magnetic domain nucleation field(HRN2) than GR grains(HRN1).After GBDP,the area of AR region increased obviously and GR region decreased accordingly,indicating that the core-shell structure could change GR grain into AR *** coreshell structure could suppress flipping of the magnetization of the grains due to the large magnetic anisotropy of Tbrich ***,large AR area led to high coercivity.

关键词： Coercivity enhancement mechanism Magnetic domain Grain boundary diffusion Nd-Fe-B sintered magnets

Study on Band Structure of YbB_6 and Analysis of Its Optical Conductivity Spectrum

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Journal of rare earths 2007年第6期25卷 654-664页

作者：姜骏卞江黎乐民 Beijing national Laboratory of Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University

The electronic structure of YbB6 crystal was studied by means of density functional （GGA ＋ U） method. The calculations were performed by FLAPW method. The high accurate band structure was achieved. The correlation between the feature of the band structure and the Yb-B6 bonding in YbB6 was analyzed. On this basis, some optical constants of YbB6 such as reflectivity, dielectric function, optical conductivity, and energy-loss function were calculated. The results are in good agreement with the experiments. The real part of the optical conductivity spectrum and the energy-loss function spectrum were analyzed in detail. The assignments of the spectra were carried out to correlate the spectral peaks with the interband electronic transitions, which justify the reasonable part of previous empirical assignments and renew the missed or incorrect ones.

关键词： YbB6 band structure optical conductivity energy-loss function spectrum assignment rare earths

Preparation of BaPbO_3 functional ceramics from leaded waste

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rare Metals 2014年第5期33卷 598-603页

作者： Bin Li Shen-Gen Zhang Kun Zhang De-An Pan Jian-Jun Tian Hu Liu Alex A.Volinsky Institute for Advanced materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing Beijing Nonferrous Metals and rare earth research Institute Department of Mechanical engineering University of South Florida

In this study, Pb was separated and used to prepare BaPbO3 conductive ceramics from leaded *** experimental results show that BaPbO3 powder synthesized at 700 °C has particle size of 2–5 lm. The powders were densified by sintering at 1,000 °C for 2 h in the *** BaPbO3 ceramics have high Curie temperature and high-temperature positive temperature coefficient（PTC） resistivity characteristics. Electrical resistivity of BaPbO3 compact increases from 5 × 10^-6Ω·m at room temperature to 4 × 10^-4Ω·m at 750 °C. Compared with the one prepared by pure chemical reagents, the BaPbO3 prepared from leaded waste has the similar characteristics of high Curie temperature and PTC resistivity.

关键词： BaPbO3 Leaded waste Positive temperature coefficient(PTC)

Study on Low Temperature Coefficient rare-earth Magnets

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Journal of rare earths 2005年第S1期23卷 263-266页

作者：常颖潘驰喻晓军潘伟李卫连法增 School of materials and metallurgy Northeastern University Shenyang 110004 ChinaDepartment of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China School of Mechanical engineering University of Science & Technology Beijing Beijing 100083 China Department of functional materials Central Iron & Steel Research Institute Beijing 100081 China School of materials and metallurgy Northeastern University Shenyang 110004 China

The rare-earth hard magnets with lower temperature coefficient, including Nd_2Fe_ 14B/Fe_3B-ferrite compound bonded magnets and Sm_ 0.8RE_ 0.2 (Co_ balFe_ 0.22Cu_ 0.06Zr_ 0.03)_ 7.4(RE=Gd, Er) sintered magnets, were studied. The result shows that the addition, that dope ferrite magnetic powder to double-phase nanocomposite Nd_2Fe_ 14B/Fe_3B magnetic powder, can make β_ jH_c to be obviously decreased. Similarly, the effect of homogeneous heating treatment on magnetic properties was studied. Doping heavy rare earth elements to the 2∶17-type SmCo magnet material powders shows that the sintered magnets obtained lower temperature coefficient, and enhanced magnets temperature stability.

关键词： temperature coefficient rare-earth hard magnets homogeneous heating treatment

Coercivity enhancement mechanism of grain boundary diffused Nd-Fe-B sintered magnets by magnetic domain evolution observation

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Journal of rare earths 2021年第6期39卷 682-688,I0003页

作者： Weiqiang Liu Yi Li Dan Wu Ming Yue Zhanjia Wang Shanshun Zha Youhao Liu Xiaofei Yi Yihui Du Key Lab of Advanced functional materials Ministry of EducationCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China State Key Laboratory of rare earth Permanent Magnetic materials.Hefei 231500 China earth-Panda Advanced Magnetic materials Co. Ltd.Hefei 231500China

The grain boundary diffusion(GBD) technology was used to prepare high performance Nd-Fe-B sintered magnets by NdH3 and TbH3 nanoparticle *** factors affecting the coercivity of GBD magnets include distribution of rare earth rich grain boundary phase and substitution of the heavy rare *** order to distinguish the influence of various factors on the coercivity,the microstructure and magnetic domain evolution of the original,reference,Nd-diffused,and Tb-diffused magnets were *** core-shell structure formed by heavy rare earth substitution is the main factor of coercivity enhancement,and it can transform the magnetic domain reversal mode from easy-nucleation(EN) to difficultnucleation(DN).With increasing the diffusion depth,the shell of the core-shell structure gradually becomes thinner,DN grains gradually decrease while the EN grains gradually increase,indicating that the magnetic domain reversal mode is directly related to the core-shell structure.

关键词： Nd-Fe-B sintered magnet Heavy rare earth Coercivity Grain boundary diffusion Core-shell structure Magnetic domain reversal

A novel Ce(Ⅳ)ion-selective polyvinyl chloride membrane electrode based on HDEHP and HEH/EHP

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Journal of rare earths 2017年第9期35卷 934-940页

作者：何金桂李勇薛向欣茹红强黄小卫杨合 Department of Resources and Environment School of MetallurgyNortheastern UniversityShenyang 110819China Liaoning Key Laboratory of Recy-cling Science for Metallurgical Resources Shenyang 110819China School of materials Science and engineering Northeastern UniversityShenyang 110819China national engineering research Center for rare earth materials General Research Institute for Nonferrous Metalsand Grirem Advanced Materials Co.Ltd.Beijing 100088China

A novel Ce（Ⅳ） ion-selective polyvinyl chloride（PVC） membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce（Ⅳ） ion were investigated, such as membrane composition, internal solution, concentration of SO_4^（2–）, and acidity in test solution. The best performance was obtained using the membrane with PVC：DBP：HDEHP：HEH/EHP：OA mass ratio of 75：175：5：5：5. The proposed electrode exhibited a Nernstian slope of 30.44 mV/decade for Ce（Ⅳ） ion over a linear concentration range of 1×10^（–5）–1×10^（–1） mol/L with the detection limit of 9.0×10^（-6） mol/L. The electrode showed stable response within the SO_4^（2–） concentration range of 0.1–1 mol/L and the acidity range of 0.25–1.2 mol/L H＋. The proposed electrode showed high selectivity for Ce（Ⅳ） over a wide variety of interfering ions and a fast response time. It was used as an indicator in the potentiometric titration of Ce（Ⅳ） solution with H_2O_2 solution, and could also be used for the determination of Ce（Ⅳ） in real Ce（Ⅳ）-containing aqueous samples.

关键词： Ce(Ⅳ) ion-selective electrode HDEHP HEH/EHP PVC membrane potential response rare earths

functional-template directed self-assembly(FTDSA) of mesostructured organic-inorganic hybrid materials

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Science China Chemistry 2009年第11期52卷 1759-1768页

作者： LI LeLe SUN LingDong ZHANG YaWen m YAN ChunHua Beijing national Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications&PKU-HKU Joint Lab in Rare Earth Materials and Bioinorganic ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Since the discovery of a surfactant directed self-assembly approach for the fabrication of mesoporous silica in 1992,increasing attention has been focused on the design and synthesis of mesostructured functional *** functionalization is becoming a major topic in this research field,since highly ordered mesostructured organic-inorganic hybrids offer novel functionalities and enhanced performance over their individual *** begin with a brief overview of the three fundamental methods(post-synthetic grafting technique,co-condensation method,and preparation of periodic mesoporous organosilicas) for the preparation of organically functionalized mesostructured silica,and focus on one of the most promising approaches,which herein was named as functional-template directed self-assembly(FTDSA) approach,and in the eyes of the authors it has a special position in the preparation of this class of hybrid materials.A comprehensive overview of the state of research in the area of FTDSA and its potential applications will be given.

关键词： mesoporous materials self-assembly organic-inorganic hybrids