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Chemically synthesizing exchange-coupled SmCo_(5)/Sm_(2)Co_(17) nanocomposites

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Rare Metals 2021年第3期40卷 575-581页

作者： Yao-hui Xu Qiang Jiang Kun Li zhen-hui ma School of Physics and Electronic Engineering Laboratory for Functional MaterialsLeshan Normal UniversityNanjing 211189China Jiangsu Key Laboratory for Design and manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing 211189China College of materials Science and Engineering Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of TechnologyBeijing 100124China Department of Chemistry Brown UniversityProvidenceRI 02912USA

A new strategy to chemically synthesize exchange-coupled SmCo_(5)/Sm_(2) Co_(17) nanocomposites by in situ decomposition of SmCox(5 详细信息

A new strategy to chemically synthesize exchange-coupled SmCo_(5)/Sm_(2) Co_(17) nanocomposites by in situ decomposition of SmCox(5magnetization(Ms)of 0.0671 A·m^(2)·g^(-1).By changing the Sm/Co to 1:4.5,1:4.8 and 1:5.2,SmCo_(5)/Sm_(2) Co_(17) nanocomposites with different proportions were acquired using the same *** to the in situ decomposition of SmCo_(x) intermediate,the small size(both of their size less than 10 nm)and uniform phase distribution were achieved in our ***,the as-prepared nanocomposites display a strong exchange-coupling *** a consequence,SMCo_(5)/Sm_(2)Co_(17)(Sm/Co=1:5.2)exhibits a coercivity of 1.23 T and enhanced M7 T(magnetization at 7 T)of 0.0812 A·m^(2)·g^(-1),increasing by 21%than pure SmCo_(5).Our synthesis provides a new protocol to prepare exchange-coupled high-performance nanocomposites.

关键词： SmCo_(5) Nanocomposites Exchange coupling Coercivity

A facile synthesis of magnetite single-crystal particles by employing GO sheets as template for promising application in magnetic fluid

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Rare Metals 2019年第8期38卷 764-769页

作者： zhen Qin zhen-hui ma Jian-Kang Zhi Yong-Ling Fu School of Mechanical Engineering and Automation Beihang University Beijing 100083China College of materials Science and Engineering Beijing University of Technology Beijing 100124China

It was reported a facile strategy to fabricate magnetite(Fe3O4)single-crystal particles with critical single-domain size by employing graphene oxide(GO)sheets as *** this method,the small-sized Fe2 O3 nanoparticles were first synthesized,and then low-temperature annealing under H2 would convert them into large-sized Fe3 O4 single-crystal *** synthetic particles with an average size of 100 nm exhibit high saturation magnetization(Ms)of 0.085 A·m^2·g^-1,which is very close to theoretical value,being among the highest values in ever reported for Fe3O4 made from chemical *** this basis,the small-sized Fe3 O4 particles(average size of 30 nm)were also fabricated by coating with Na2 CO3 shell.

关键词： Fe3O4 Critical single-domain size Saturation magnetization Chemical synthesis

Synthesis of SmCo_5 nanoparticles with small size and high performance by hydrogenation technique

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Rare Metals 2018年第12期37卷 1021-1026页

作者： zhen-hui ma Tian-Li Zhang hui Wang Cheng-Bao Jiang School of materials Science and Engineering Beihang University

SmConanoparticles(NPs) have promising applications in high-density magnetic storage and magnetic nanocomposites. In this work, A novel method to yield SmCoparticles with small size and high coercivity was reported. Firstly, SmO-Co NPs with size of 6-15 nm were fabricated by a solvothermal route. Then the agglomerated SmCoparticles were obtained by thermal reduction of the precursor, which show high coercivity of2.0 T at room temperature. At last, the as-synthesized SmCoparticles were further hydrogenated under high hydrogen pressure of 4 MPa at room temperature, where hydrogen absorption process could form small-sized SmCoHparticles due to their lattice expansion and hydrogen desorption process could convert SmCoHNPs into SmCoNPs. The prepared SmCoNPs after hydrogenation, showing well distribution, have a small size of5-20 nm and room temperature coercivity of 1.22 T.

关键词： SmCo_5 Nanoparticles Hydrogenation Coercivity

2D/2D heterostructured MoS_(2)/PtSe_(2) promoting charge separation in FTO thin film for efficient and stable photocatalytic hydrogen evolution

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Rare Metals 2022年第5期41卷 1735-1742页

作者： Shu-Tong Wan Hao-Tong Li zhen-hui ma He-Chuan Zhang Yan-zhen zheng Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Department of Physics Beijing Technology and Business UniversityBeijing 100037China

Exploiting stable photocatalytic films is of practical significance for solar energy-hydrogen conversion and pollutant degradation, yet remains a big challenge so far. In this work, we report a highly stable photocatalytic film, i.e.,MoS_(2)/PtSe_(2)/FTO by sequential growing PtSe_(2) and MoS_(2) onto commercially fluorine-doped tin oxide(FTO) substrates using two round thermal evaporation and chemical vapor deposition(CVD) process.

关键词： film FTO separation

Chemical synthesis of SmCo5/Co magnetic nanocomposites

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Rare Metals 2019年第4期38卷 306-311页

作者： Run-Bo Lu zhen-hui ma Tian-Li Zhang Cheng-Bao Jiang School of materials Science and Engineering Beihang University

A three-step chemical synthesis of SmCo5/Co nanocomposites was developed. Firstly, the Co-Sm（OH）3-Ca（OH）2 precursors were prepared by ***, SmCo5 particles were obtained by reductive annealing of the precursors. At last, the SmCo5/Co nanocomposites were achieved by chemical deposition based on SmCo5 particles. The SmCo5/Co nanocomposites contain hard magnetic phase of SmCo5 with about 100 nm in size and soft magnetic phase of Co with about 8 nm in size,exhibiting independent two-phase structure without alloying. Compared to that of single-phase SmCo5 particles, the saturation magnetization of SmCo5/Co nanocomposites is increased by 27.5%. The synthesis provides a new route to fabricate SmCo-based nanocomposites.

关键词： magnetic nanocomposites SmCo5/Co Three-step chemical synthesis

Ferrite-based composites and morphology-controlled absorbers

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Rare Metals 2022年第9期41卷 2943-2970页

作者： Yu Mu zhen-hui ma Hong-Sheng Liang Li-Min Zhang Hong-Jing Wu MOE Key Laboratory of material Physics and Chemistry Under Extraordinary School of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an710072China Department of Physics Beijing Technology and Business UniversityBeijing100037China

The exploration of lightweight and efficient electromagnetic wave(EMW)absorption materials is a crucial focus topic because the human body and precision instruments are exposed to the increasingly serious electromagnetic ***,as the first type of EMW absorption material,is still the indelible superstar in the EMW absorption field due to its unique double loss mechanism,controllable morphology and high *** review briefly introduces the EMW absorption and attenuation mechanism of ferrite-based composite absorbers,including dielectric loss dominated by charge transfer and polarization relaxation,and magnetic loss consisted of eddy current and ***,we comb the advances in synthesis of ferrite *** particular,this paper summarizes the advantages and defects of pure ferrite as EMW absorption *** the approach to tackling the imbalance of impedance matching and highdensity in ferrite is also reviewed,including ion substitution,design of micro-morphology and doping with dielectric loss materials.

关键词： Electromagnetic wave absorption(EMWA) Ferrite Attenuation mechanism Synthetic method Modification

Doping engineering of iron oxide nanoparticles towards high performance and biocompatible T_(1)-weighted MRI contrast agents

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Rare Metals 2024年第1期43卷 298-308页

作者： Xue Xu Ping-Li Dong Yu-Yun Chai Run Yang zhen-hui ma Chi-Chong Lu Department of Chemistry College of Chemistry and Materials EngineeringBeijing Technology and Business UniversityBeijing 100048China Department of Physics Beijing Technology and Business UniversityBeijing 100048China

Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast *** when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor *** doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed ***,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and ***,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal ***,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding ***_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)*** stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.

关键词： Iron oxide nanoparticles Small size magnetic resonance imaging Substitutional doping Gd dopant

Schiff-base-rich g-C_(x)N_(4) supported PdAg nanowires as an efficient Mott-Schottky catalyst boosting photocatalytic dehydrogenation of formic acid

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Rare Metals 2021年第4期40卷 808-816页

作者： Hu Liu Xue-Xiang Li Xin-Yang Liu zhen-hui ma Zhou-Yang Yin Wei-Wei Yang Yong-Sheng Yu School of Chemistry and Chemical Engineering Xi’an University of Architecture and TechnologyXi'an 710055China School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi'an 710072China MIIT Key Laboratory of Critical materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China Department of Chemistry Brown UniversityRI 02912USA

Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) ***,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem rings conjugated by Schiff-base bond(N=C-C=N) was synthesized,tuning the bandgaps(Eg) of graphitic carbon nitride(g-C_(3) N_(4)) in the range of 1.8 400 nm) without any additive at 25℃,which is the best value among ever-reported *** work provides a new strategy to boost dehydrogenation photocatalysis of FA,which will be promising for practical application of H2 in future energy field.

关键词： Dehydrogenation of formic acid Graphitic carbon nitride Schiff base PdAg nanowires Mott-Schottky heterojunction

Room-temperature hydrogen spillover achieving stoichiometric hydrogenation of NO_(3)^(-) and NO_(2)^(-) into N_(2) over CuPd nanowire network

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Rare Metals 2022年第3期41卷 851-858页

作者： Ruo-Yan Miao Xue-Xiang Li Qian Lei Hu Liu zhen-hui ma Xu-Dong Liu Zhou-Yang Yin Zuo-Bin Tang Liang Zhang Yu-Hong Tian School of Chemistry and Chemical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710072China Department of Physics Beijing Technology and Business UniversityBeijing 100048China Department of Chemistry University of VirginiaCharlottesvilleVA 22904USA

The development of an efficient hydrogen spillover (HS)catalyst achieves the stoichiometric chemoselective hydrogenation of NO_(3)^(-)and NO_(2)^(-)into N_(2) at room temperature,which is extremely ***,we report a Cu_(x)Pd_(1-x) nanowire network (NWN)(x=7,5,or 3) with tunable hydrogen spillover rate of formic acid (FA) with polyvinylpyrrolidine imine (PVPI) modifying its surface.

关键词： network hydrogen (3)