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Surface organic modification of Fe_3O_4 nanoparticles by silane-coupling agents

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Rare Metals 2006年第Z1期25卷 426-430页

作者： CUI sheng shen xiaodong LIN Benlan College of Material Science and Technology Nanjing University of Technology Nanjing 210009 China College of Material Science and Technology Nanjing University of Technology Nanjing 210009 China College of Material Science and Technology Nanjing University of Technology Nanjing 210009 China

Fe3O4 nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic micro-spheres dispersed in organic medium glycol were gained and the mean size of Fe3O4 nanopowders was 33.7 nm. So it can be concluded that magnetic micro-sphere is made of a few Fe3O4 crystals. Many factors of modification were researched, such as the time of ball milling, the content of Fe3O4 and the content of KH570. The modification of Fe3O4 is relative to the time of ball milling, but the dominant function is affected by the content of Fe3O4 and KH570. When the content of Fe3O4 is known, there is a suitable content of KH570. Different content of Fe3O4 will make the different suitable content of KH570, but the range of latter is less than former, which is relative to the distribution of KH570 on Fe3O4 surface or in the solution.

关键词： Fe3O4 nanoparticles organic modification silane-coupling agents

Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 562-573页

作者： Qianqian Wang Zequn Yao Lijie Guo xiaodong shen College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology Group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions

Electrochemical properties of Co-S/x wt.% AB_5 composite materials

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Science China(Technological Sciences) 2015年第8期58卷 1355-1359页

作者： LI JiaJia ZHAO XiangYu HU LiNa MA LiQun shen xiaodong College of Materials Science and Engineering Nanjing Tech University

The Co-S/x wt.% AB5 （x=0, 10, 20, 30） composite materials were prepared by simply mixing Co-S material fabricated by hy- drothermal method and AB5 alloy. The structure and morphology of the composite materials were characterized by XRD and SEM, respectively. The electrochemical properties of the composite electrodes were studied by the galvanostatic charge, dis- charge test and electrochemical impedance spectroscopy. The results showed that the Co-S/20 wt.% AB5 composite electrode showed the highest discharge capacity and the best cycling stability. The existence of the AB5 alloy improved the electro- chemical activity of composite electrodes, reduced the electrochemical polarization resistances and promoted the electrochem- ical conversion reaction between Co and Co（OH）2. In order to improve the utilization rate of active materials, 0.0! mol/L Na2S203 was added into the electrolyte. The electrochemical properties of the composite electrode were significantly enhanced. After fifty cycles, the discharge capacity of the composite electrode increased from 407 to 481.7 mAh/g and the capacity reten- tion increased from 79.7% to 91.2%.

关键词： Co-S AB5 hydrogen storage alloy composite materials electrochemical properties

Preparation and Adsorption Property of Phenyltriethoxysilane Modified SiO_2 Aerogel

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Journal of Wuhan University of Technology(Materials Science) 2013年第5期28卷 916-920页

作者：林本兰崔升 LIU Xueyong LIU Yu shen xiaodong HAN Guifan State Key Laboratory of Materials-Oriented Chemical Engineering College of Materials Science and EngineeringNanjing University of Technology Institute of Chemical Materials The Chinese Academy of Engineering Physics

The hydrophobic silica aerogel （SiO2 aerogel） was prepared by/n situ polymerization sol-gel method and ethanol supercritical drying, with tetraethoxysilane （TEOS） as silica source, phenyltriethoxysilane （PTES） as modifier, ethanol as solvent and ammonia as catalyst. The effects of n（PTES）/n（TOES） were investigated on gel time, structure, and hydrophobicity. The SiO2 aerogel was measured by Fourier transform infrared spectroscopy （FT-IR） and scanning electron microscopy （SEM）. The effects of n（PTES）/n（TOES） were also studied on adsorption property of pentane, hexane, heptane, octane, benzene, toluene, o-xylenc, nitromethane, nitroethane, and nitrobenzene. The adsorption intensity of SiO2 aerogel was compared with that of activated carbon. The results show, with the increasing ofn（PTES）/n（TOES）, the surface area, pore volume, and pore size of SiO2 aerogel decreased, gel time and hydrophobicity increased, and the contact angle could be 154° with n（PTES）/n（TOES）=0.7. The adsorption intensity of SiO2 aerogel with n（PTES）/n（TOES）=0.5 was bigger than that of activated carbon with an average 5.84 times of 10 organic liquid. The adsorption intensity of aerogel with n（PTES）/n（TOES） =0.1 was the best one in all samples with the average 8.33 times compared with that of activated carbon.

关键词： silica aerogel hydrophobicity PTES adsorption intensity activated carbon

Surface Organic Modification of Fe_3O_4 Magnetic Nanoparticles

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Journal of Wuhan University of Technology(Materials Science) 2008年第4期23卷 436-439页

作者： CUI sheng shen xiaodong LIN Benlan JIANG Guodong ZHANG Weihua College of Material Science and Technology Nanjing University of Technology Nanjing 210009 China

The surface organic modification of Fe3O4 nanoparticles with silane coupling reagent KH570 was studied. The modified and unmodified nanoparticles were characterized by FT-IR, XPS and TEM. The spectra of FT-IR and XPS revealed that KH570 was coated onto the surface of Fe3O4 nanoparticles to get Fe-O- Si bond and an organic coating layer also was formed. Fe3O4 nanoparticles were spheres partly with mean size of 18,8 nm studied by TEM, which was consistent with the result 17.9 nm calculated by Scherrer＇s equation. KH570 was adsorbed on surface and formed chemistry bond to be steric hindrance repulsion which prevented nanoparticles from reuniting. Then glycol-based Fe3O4 magnetic liquids dispersed stably was gained.

关键词： Fe3O4 nanoparticles KH570 surface organic modification chemical adsorb dispersivity

High mass loading Ni_(4)Co_(1)-OH@CuO core-shell nanowire arrays obtained by electrochemical reconstruction for alkaline energy storage

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Nano Research 2022年第1期15卷 685-693页

作者： Yawei Yu Xiulan Hu Shuai Wang Handan Qiao Zeyu Liu Kefan Song xiaodong shen College of Materials Science and Engineering Nanjing Tech UniversityPuzhu South Road No.30Nanjing 211816China The Synergetic Innovation Center for Advanced Materials Nanjing Tech UniversityPuzhu South Road No.30Nanjing 211816China Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech UniversityPuzhu South Road No.30Nanjing 211816China

The design of three-dimensional(30)core-shell hetercistructures is an efficient method to achieve high mass specific capacity of electroactive materials under high mass *** this work,porous Ni_(4)Co1-0H nanosheets with a mass loading of 7.7 mg·cm^(-2) are obtained by using Ni_(4)Cor(NO_(3))_(2)(0H)_(4) supported on the CuO nanowires as precursors via an unavoidable electrochemically induced phase *** the electrochemical reconstruction process,the N03-anions in Ni_(4)Cor(N0_(3))_(2)(0H)_(4) are easily replaced by OH-anions in the *** phase reconstruction is accompanied by the decrease of ionic diffusion.:resistance and the increase of pore volume,and the shift of binding *** obtained Ni4Co1-0H nanosheets show a high:mass specific capacity of 363.6 mAh·g^(-1) at 5 mA·cm^(-2).The as-fabricated alkaline hybrid supercapacitor and Ni-Zn battery deliver high energy density of 293.1 and 604.9 Wh·kg^(-1),respectively,*** alkaline energy storage performance.

关键词： electrochemical reconstruction core-shell heterostructure high mass loading alkaline hybrid supercapacitor Ni-Zn battery

Effect of CuO on the Formation Mechanism of Calcium Sulphoaluminate

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Journal of Wuhan University of Technology(Materials Science) 2008年第4期23卷 518-521页

作者： MA Suhua shen xiaodong HUANG Yeping ZHONG Baiqian College of Materials Science and Engineering.Nanjing University of Technology Nanjing 210009 China

Calcium sulphoaluminate was prepared with chemical reagents in this paper. The formation mechanism of calcium sulphoaluminate and effect of CuO on the formation mechanism of calcium sulphoaluminate were investigated by the chemical analysis, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC）. The results show that there are three ways in the formation of calcium sulphoaluminate. CuO can promote the decomposition of calcium carbonate and decrease the formation temperature of calcium sulphoaluminate（C4A3S）. When the burning temperature is below 1 000 ℃, the addition of CuO can promote the formation of calcium sulphoaluminate, while CuO can not favor the formation of calcium sulphoaluminate above 1 000 ℃.

关键词： copper oxide calcium sulphoaluminate formation mechanism

Diffusion Characteristic of Sulfate Anion in Surface Region of Cement Mortar at Early Stage

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Journal of Wuhan University of Technology(Materials Science) 2017年第2期32卷 358-364页

作者：王学兵潘志华 shen xiaodong CHEN Yangyi LIU Weiqing College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 China College of Civil Engineering Nanjing Tech University Nanjing 210009 China

The SO4^（2-）concentration distributions in surface region of cement mortar immersed in sulfate solution at early stage were measured by layered sampling method combined with chemical analysis, and the diffusion coefficients of SO4^（2-）anions in surface region of mortar into internal area were calculated by means of instantaneous plane diffusion theory. The experimental results showed that the SO4^（2-）concentration gradually reduced when the diffusion depth increased in the surface region of mortar. Diffusion coefficient（D） was relevant with the concentration and kind of environmental sulfate solution, which reduced with immersion time at the beginning, and then rose slowly after a period of time. The calculation of initial diffusion coefficient（D0） and starting time of deterioration（t∞） caused by sulfate attack was further attempted based on the data of diffusion coefficient, and it was found that D0 and t∞ were all relevant with concentrations of sulfate and different kind of sulfate as well.

关键词： cement mortar sulfate attack diffusion coefficient

Densification,microstructure,and fracture behavior of TiC/Si_3N_4 composites by spark plasma sintering

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Rare Metals 2008年第3期27卷 315-319页

作者： BAI Ling GE Changchun shen Weiping MAO xiaodong ZHANG Ke Laboratory of Special Ceramics and Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China

TiC/Si3N4 composites were prepared using the β-Si3N4 powder synthesized by self-propagating high-temperature synthesis （SHS） and 35 wt.% TiC by spark plasma sintering. Y2O3 and Al2O3 were added as sintering additives. The almost full sintered density and the highest fracture toughness （8.48 MPa·m1/2） values of Si3N4-based ceramics could be achieved at 1550℃. No interfacial interactions were noticeable between TiC and Si3N4. The toughening mechanisms in TiC/Si3N4 composites were attributed to crack deflection, microcrack toughening, and crack impedance by the periodic compressive stress in the Si3N4 matrix. However, increasing microcracks easily led to excessive connection of microcracks, which would not be beneficial to the strength.

关键词： silicon nitride titanium carbide spark plasma sintering (SPS) microstructure fracture behavior