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Mechanistic insight into the synergy between nickel single atoms and nanoparticles on N-doped carbon for electroreduction of CO2

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Journal of Energy Chemistry 2025年第1期100卷 327-336页

作者： Mingdong Sun Wenwen Guan Cailing Chen Chao Wu Xiaoling Liu Biao Meng Tao Chen Yu Han Jun Wang Shibo Xi Yu Zhou State Key Laboratory of materials-Oriented Chemical Engineering College of Chemical Engineering Nanjing Tech University Advanced Membranes and Porous materials Center Physical Sciences and Engineering Division King Abdullah University of Science and Technology Institute of Sustainability for Chemicals Energy and Environment A*STAR (Agency for Science Technology and Research) College of materials Science and Engineering Sichuan University

The synergy of single atoms （SAs） and nanoparticles （NPs） has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction （CO2RR）;however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst ***,a Ni2+-loaded porous poly（ionic liquids）(PIL) precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing *** catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO2into *** Ni K-edge X-ray absorption near-edge structure （XANES） spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and *** charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active *** the electroreduction of CO2,the coexistence of Ni SAs and NPs strengthened the CO2activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO2→*COOH step,and therefore promoted the catalysis efficiency.

关键词： Single atom catalyst Synergy effect Carbon catalyst Electrocatalysis

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A cellulose-based lithium-ion battery separator with regulated ionic transport and high thermal stability for extreme environments

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Nano Research 2025年第1期18卷 315-322页

作者： Kun-Peng Yang Song Xie Zi-Meng Han Hao-Cheng Liu Chong-Han Yin Wen-Bin Sun Zhang-Chi Ling Huai-Bin Yang De-Han Li Qing-Fang Guan Shu-Hong Yu Department of Chemistry New Cornerstone Science LaboratoryInstitute of Biomimetic Materials&ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&ChemistryHefei National Research Center for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei 230026China Institute of Innovative materials Department of Materials Science and EngineeringDepartment of ChemistrySouthern University of Science and TechnologyShenzhen 518055China

Separators play a critical role in lithium-ion ***,the restrictions of thermal stability and inferior electrical performance in commercial polyolefin separators significantly limit their applications under harsh ***,we report a cellulose-assisted self-assembly strategy to construct a cellulose-based separator massively and *** an ultrahigh ionic conductivity in electrolytes of 3.7 mS·cm^(-1) and the ability to regulate ion transport,the obtained separator is a promising alternative for high-performance lithium-ion *** addition,integrated with high thermal stability,the cellulose-based separator endows batteries with high safety at high temperatures,greatly expanding the application scenarios of energy storage devices in extreme environments.

关键词： lithium-ion batteries bio-inspired materials battery separators cellulose nanofiber ultrahigh ionic conductivity high safety

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Oxide evolution in NdDy-Fe-B magnet during aging process

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Journal of Rare Earths 2012年第10期30卷 1020-1023页

作者：王景代冯海波李安华李岩峰朱明刚李卫 division of functional materials Central Iron and Steel Research Institute

Sintered NdDy-Fe-B magnets were made from strip cast flakes by powder metallurgy method. For the magnet with 6 wt.% Dy substituted Nd, a remarkable coercivity increase of 70% was obtained after aging at 900 ℃ for 2 h and a high coercivity of 23.5 kOe was achieved after aging at 520 ℃ for 2 h. The average diameter of the oxide particles decreased during the following 900℃ aging treatment. Dy and O diffusion from oxide particles to Nd-rich phase during the aging process was observed. The oxide evolution and Dy element diffusion were helpful to the coercivity enhancement.

关键词： permanent magnet aging dysprosium oxide coercivity rare earths

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Optimization of microstructures and magnetic properties of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023))_(7.6) magnets by sintering treatment

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Journal of Rare Earths 2019年第2期37卷 171-177页

作者： Kuikui Songa Wei Suna Yikun Fang Shuai Wang Nengjun Yu Meiling Zhang Minggang Zhu Wei Li division of functional materials Research Central Iron and Steel Research Institute

Magnetic properties and microstructures of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023_)_(7.6) sintered magnets were optimized by sintering treatment. Results show that the knee-point magnetic field, Hknee, is twofold up and the intrinsic coercivity Hcjincreases by 40%, ranging from 21.64 to 30.39 kOe at the cost of a little decrease of Brfrom 10.84 to 10.31 kGs with sintering temperature decreasing from 1488 to 1473 K. And the average domain width is narrower and more uniform for the specimen sintered at 1473 K than that of the specimen sintered at 1488 K. It is impressive that the density of lamellar phase increases from ~0.050 to ~0.058 nm^(-1) with the sintering temperature decreasing from 1488 to 1473 K. Moreover, the average cellular size is about ~84 nm for the magnets sintered at 1473 K, which is 80% of that of the magnets sintered at 1488 K(~97 nm). And the cell boundary width of the magnets sintered at 1473 K(~7 nm) is only half average width of the magnets sintered at 1488 K(~14 nm). It is found that the Cu content in the cell boundaries is much higher(~17 at%) in the magnets sintered at 1473 K compared to that of the magnets sintered at 1488 K(~10 at%). It can be concluded that smaller cells and narrower cell boundaries together with higher gradient of Cu content are key points for obtaining the optimum Hkneeand Hcj.

关键词： Sm-Co magnets Sintering Coercivity Microstructure Rare earths

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Effect of Sm-rich liquid phase on magnetic properties and microstructures of sintered 2:17-type Sm-Co magnet

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Journal of Rare Earths 2011年第10期29卷 934-938页

作者：张文臣赵睿方以坤周鸣鸽朱明刚李卫 division of functional materials Central Iron and Steel Research Institute

The effect of Sm-rich liquid phase （Sm2Co3） on magnetic properties and microstructure of 2：17-type Sin-Co magnet was studied. Three phases existed in liquid phase ingot, and took on white, dark grey and grey, respectively. It was found that the composition of the grey area was similar to the nominal one. Our results indicated that the optimal composition was obtained at 3 wt.% liquid phase added, and the magnetic properties were B^I 1.58 kGs, Hci〉26 kOe, （BH）m=29.51 MGOe. Br increased by 3%, Hci was 13 times larger, and （B/-/）m was 6 times bigger than none liquid phase magnets. Moreover, with the aging time decreasing from 20 to 8 h, the squareness of the demagnetization curves got better, while the coercivity of the samples decreased. It revealed that Sm（Co,Cu）5 phase also precipitated at particle boundaries. It maybe also enhanced the coercivity.

关键词： 2:17-type sintered magnets Sm-rich liquid phase magnetic properties scanning electron microscopy rare earths

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Hot deformation in nanocrystalline Nd-Fe-B backward extruded rings

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Chinese Physics B 2011年第10期20卷 402-406页

作者：李安华赵睿赖彬王会杰朱明刚李卫 division of functional materials Central Iron & Steel Research Institute

Radially oriented Nd-Fe-B rings are prepared by backward extrusion of fine grained melt-spun powder. Melt- spun powder with the nominal composition of ***6.0Ga0.6A10.2B0.9 （wt%） is used as starting material. The effects of process variables, such as deformation temperature （Td）, strain rate （ε） and height reduction （△h%）, on the magnetic properties of the rings are investigated. A scanning electron microscope （SEM） equipped with an energy spectrum device is used to study the metallograph and microfracture of the extruded rings. The Br and （BH）max reach the optimum values at Td =800℃,ε= 0.01 mm/s, and △h% = 70%. It is found by SEM observations that the particle boundaries, which seemingly correspond to the interfaces of the starting melt-spun powders, emerge after the corrosion of metallography specimens. This is helpful for studying the effects of powder-powder interface on the local deformation and deformation homogeneity in the rings. For different spatial positions of the extruded rings, there are characteristic metallographies and microfractures. The upper end of the rings has the least deformation and worst texture, and therefore the worst magnetic properties. The magnetic properties in the radial direction increase slightly along the axis from the bottom to the middle, then steeply decrease at the upper end of the ring. The deformation and the formation-of-texturing processes are discussed. The deformation and the texturing formation of melt-spun Nd-Fe-B alloys probably involve grain boundary sliding and grain rotation, the solution-precipitation process and preferential growth of Nd2Fel4B nanograins along the easy growth a-axis.

关键词： radially oriented Nd-Fe-B rings backward extrusion microstructure texture

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Quasi-periodic layer structure of die-upset NdFeB magnets

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Journal of Rare Earths 2013年第7期31卷 679-684页

作者：赖彬李岩峰王会杰李安华朱明刚李卫 division of functional materials Central Iron&Steel Research Institute

Isotropic magnets were prepared from melt-spun powders at different hot pressing temperatures from 550 to 700 ℃, then upset into fully dense anisotropic magnets at the same die-upsetting temperature of 850 ℃. Die-upset magnets had the characteristics of inhomogeneous microstructure, including well-aligned grains structure and nonaligned grains layers transverse to press direction, which was quasi-periodic layer structure with a total length of 5-15 μm. Nonaligned grains layers were mainly made of large grains and had higher Nd content. To clearly understand the formation of layer structure, the microstructure of isotropic precursors with different hot pressing temperatures and their subsequent die-upset magnets was investigated. A new interpretation for the formation of layer structure was proposed in this paper： the layer structure was correlated to the original ribbon interface which was divided into three types based on the contact forms. Because of the incomplete contact of neighboring ribbons, concentration of stress occurred in the contacted points and the Nd-rich phase was squeezed into interspaces at high temperature under stress. Due to the release of interfacial energy and the fluidity of enough Nd-rich liquid phases, the nonaligned layers with large grains formed both in hot compaction and subsequent hot deformation process. The layer structure affected the magnetic properties of die-upset magnets. With increase of the hot pressing temperature, the nonaligned grains layers became thicker, and the magnetic performance of die-upset magnets decreased. It was necessary to reduce the thickness of large grains layers for the preparation of high-performance die-upset magnets.

关键词： die-upset magnets anisotropic layer structure coarse grains rare earths

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Microstructure and magnetic properties of sintered CeCo_(4.3252-x)Cu_(0.675)Fe_x magnets

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Rare Metals 2015年第3期34卷 164-167页

作者： Wei Sun Ming-Gang Zhu Yi-Kun Fang Wei Pan Man-Long Xia Wei Li division of functional materials Central Iron and Steel Research Institute Group

Anisotropic CeCo4.325_xCuo.675Fex （x ： 0.475- 0.875） sintered magnets were prepared by traditional powder metallurgical method. Influence of ball-nfilling time and iron content on microstructure and magnetic properties of the CeCo4,325-xCuo.675Fex sintered magnets were investigated. It is shown that the properties of the magnet produced by mag- netic powders ball-milled for 40 min are better than that for 30 rain. With iron content increasing, remanence Br and maxi- mum energy product （BH）m increase first and then decrease. The optimal magnetic properties are obtained for the CeCo3.65Cuo.675Feo.675 sintered magnet： Br=0.685 T, the intrinsic coercivity Hci = 350 kA.m-1, and （BH）m ： 85.6 kJ.m-3. The increase of Br is mainly influenced by iron content of 1：5 matrix which can properly increase the saturation induction Bs; the rapid increase of the amount of Ce-rich phase and 5：19 phase gives rise to the deterioration of the magnets when x ≥ 0.775.

关键词： Ce-Co-based permanent magnet Remanence Microstructure

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Statistical model of magnetization reversal in Nd-Fe-B sintered magnets

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Rare Metals 2006年第Z1期25卷 521-525页

作者： WANG Huijie ZHU Minggang LI Wei ZHANG Xin division of functional materials Central Iron & Steel Research Institute Beijing 100081 China Division of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China Division of Functional Materials Central Iron & Steel Research Institute Beijing 100081 China China Petroleum Materials Tianjin Corporation Tianjin 300204 China

Statistical model of magnetization reversal was used to simulate the magnetization reversal behavior in the sintered Nd-Fe-B magnets with double grain-size distributions due to the abnormal grain growth (AGG). The magnetic properties and mechanical properties due to the formation of AGG grains in Nd-Fe-B sintered magnets were tested. The results show that the magnetic properties, especially the rectangularity were severely deteriorated after the formation of the AGG grains and a step was shown on the demagnetization curve, and the occurrence of AGG may account for the poor rectangularity and existence of the step on demagnetization curve according to the statistical model of magnetization reversal. The fracture toughness and bending strength are lowered because of the stress concentration in the AGG grains. The SEM images show that the formation of AGG grains is caused by the solid sintering due to the absence of RE-rich phase. Statistical model of magnetization reversal can qualitative by explain the dependence of the magnetization reversal behavior on the grain size in the Nd-Fe-B sintered magnets.

关键词： sintered Nd-Fe-B magnets mechanical properties magnetization reversal abnormal grain growth

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Magnetic properties and structures of Y-substituted Nd-Y-Fe-B melt-spun ribbons

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Rare Metals 2023年第5期42卷 1712-1717页

作者： Meng Zheng Yi-Kun Fang Li-Wei Song Rui Han Ming-Gang Zhu Wei Li division of functional materials Central Iron and Steel Research InstituteBeijing100081China

The nanocrystalline magnetic ribbons of(Nd_(1-x)Y_(x))_(14.5)Fe_(ba1)B(6)Co_(0.2)Al_(1)Cu_(0.15)(x=0,0.1,0.2,0.3,0.4) were prepared by melt-spinning *** magnetic properties and microstructures were systematically investigated for the *** is found that Y substituting Nd in the R_(2)Fe_(14)B main phase grains gives rise to the decrease in the crystal lattice *** Y content increases from x=0 to x=0.4,the remanence and intrinsic coercivity(H_(cj)) decrease from 0.80 to 0.71 T and1400 to 809 kA·m^(-)1,respectively,with the corresponding descent rate of 11.5% and 42.5%.It is impressed that the average grain size increases with Y content *** the strong intergrain exchange coupling interactions exist in all the ribbons and could be enhanced with an appropriate Y substitution,such as x=***,magnetization reversal mechanism is confirmed to be pinning type for the *** results provide valuable reference to the fabrication of Y-substituted Nd-Y-Fe-B sintered magnets.

关键词： Melt-spun ribbons Y substitution Intergrain exchange coupling Microstructure

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