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Improvement of the piezoelectricity of PVDF-HFP by CoFe_(2)O_(4)nanoparticles
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作者 Dan Lei Ning Hu +5 位作者 Liangke Wu Alamusi Huiming Ning Yang Wang Zhaonan Jin Yaolu Liu 《Nano Materials Science》 EI CAS CSCD 2024年第2期201-210,共10页
High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method acc... High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling.The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments.For pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity dramatically.In the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 V.Meanwhile,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,respectively.The effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC. 展开更多
关键词 PVDF-HFP CoFe_(2)O_(4)nanoparticles PIEZOELECTRICITY NANOCOMPOSITE
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掺杂CoFe_(2)O_(4)膨胀石墨对Pb(Ⅱ)的吸附性能
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作者 姬莉 李媛媛 +1 位作者 王华 岳学庆 《非金属矿》 2024年第3期79-82,共4页
为解决膨胀石墨吸附后回收难的问题,采用柠檬酸基的溶胶-凝胶法将CoFe_(2)O_(4)粒子负载到膨胀石墨中,制备磁性膨胀石墨。利用扫描电子显微镜(SEM)和磁滞回线对样品的微观形貌和磁性能进行表征,研究了膨胀石墨和磁性膨胀石墨对Pb(Ⅱ)吸... 为解决膨胀石墨吸附后回收难的问题,采用柠檬酸基的溶胶-凝胶法将CoFe_(2)O_(4)粒子负载到膨胀石墨中,制备磁性膨胀石墨。利用扫描电子显微镜(SEM)和磁滞回线对样品的微观形貌和磁性能进行表征,研究了膨胀石墨和磁性膨胀石墨对Pb(Ⅱ)吸附性能的影响因素,包括吸附时间、Pb(Ⅱ)初始质量浓度、吸附剂用量和pH值等,并采用吸附动力学和吸附等温线模型对吸附行为及机理进行了分析。结果表明,膨胀石墨和磁性膨胀石墨对Pb(Ⅱ)的最大吸附量分别为95.6、69.8 mg/g,吸附动力学符合二级动力学模型,吸附等温线符合Langmuir模型。掺杂CoFe_(2)O_(4)粒子缩短了膨胀石墨对Pb(Ⅱ)吸附平衡所需的时间,并使最佳吸附pH值向更加中性条件迁移。 展开更多
关键词 膨胀石墨 CoFe_(2)O_(4)粒子 Pb(Ⅱ) 吸附
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基于“种子-生长”的液相法制备的CoFe_(2)O_(4)纳米颗粒及磁性能
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作者 王焱 冯治棋 +3 位作者 左显维 李昕 刘一丹 何欣 《磁性材料及器件》 CAS 2024年第3期21-26,共6页
依据不同的应用需求,实现纳米材料颗粒尺寸和形状的可控制备一直是材料制备领域研究的重点。为了研究CoFe_(2)O_(4)纳米颗粒尺寸和形状对于磁性能的影响,本文分别通过传统的液相法和基于“种子-生长”的液相法制备出了不同颗粒尺寸和形... 依据不同的应用需求,实现纳米材料颗粒尺寸和形状的可控制备一直是材料制备领域研究的重点。为了研究CoFe_(2)O_(4)纳米颗粒尺寸和形状对于磁性能的影响,本文分别通过传统的液相法和基于“种子-生长”的液相法制备出了不同颗粒尺寸和形状的CoFe_(2)O_(4)纳米颗粒并研究其磁性能。结果表明:CoFe_(2)O_(4)颗粒的尺寸和形状变化会影响纳米颗粒的分散性和矫顽力。其中,通过“种子-生长”的液相法制备的六边形CoFe_(2)O_(4)纳米颗粒的矫顽力在室温下可达383Oe,80K时高达13105Oe。 展开更多
关键词 CoFe_(2)O_(4)纳米颗粒 液相法 “种子-生长”法 形状 磁性能
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CoFe_(2)O_(4)/MXene复合材料的构筑及活化过氧单硫酸盐降解阿特拉津
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作者 曹梦寒 徐鹏 +4 位作者 石凤银 李桂鄂 张国栋 郑庆柱 张广山 《应用化学》 CAS CSCD 北大核心 2024年第2期256-267,共12页
通过微波辅助水热法将双金属氧化物(CoFe_(2)O_(4))负载在MXene上,成功制备了CoFe_(2)O_(4)/MXene复合催化剂并用于活化过氧单硫酸盐(Peroxymonosulfate,PMS)。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等技... 通过微波辅助水热法将双金属氧化物(CoFe_(2)O_(4))负载在MXene上,成功制备了CoFe_(2)O_(4)/MXene复合催化剂并用于活化过氧单硫酸盐(Peroxymonosulfate,PMS)。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等技术手段对复合催化剂的结构、形貌和元素价态进行表征,发现CoFe_(2)O_(4)被成功负载到了MXene上。以阿特拉津(ATZ)为目标污染物,研究了CoFe_(2)O_(4)/MXene活化PMS降解ATZ体系中催化剂投加量、过硫酸盐浓度和pH值等因素对ATZ降解的影响。结果表明,在pH=6.35的条件下,当CoFe_(2)O_(4)/MXene(0.1 g/L)和PMS(0.37 mmol/L)用量较低时,ATZ的降解率在15 min内达到100%;并且该体系具有较广的pH值适用范围(2~10)和应用范围;淬灭实验表明,反应体系中自由基途径和非自由基途径均存在,其中SO_(4)•^(−)、O_(2)•^(−)和^(1)O_(2)占主导作用,共同作用于ATZ的降解过程。这项研究开发了具有优异催化性能的新型材料,可为CoFe_(2)O_(4)/MXene非均相催化剂活化PMS降解有机污染物提供新思路。 展开更多
关键词 CoFe_(2)O_(4)/MXene 微波水热 过氧单硫酸盐 阿特拉津 活性物种
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Structural and microwave absorption properties of CoFe_(2)O_(4)/residual carbon composites
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作者 Yuanchun Zhang Shengtao Gao +3 位作者 Xingzhao Zhang Dacheng Ma Chuanlei Zhu Jun He 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期221-232,共12页
Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_... Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_(4)/residual carbon from coal gasification fine slag(CFO/RC)composites were created using a novel hydrothermal method.Various mechanisms for microwave absorption,including conductive loss,natural resonance,interfacial dipole polarization,and magnetic flux loss,are involved in these composites.Consequently,compared with pure residual carbon materials,this composite offers superior capabilities in microwave absorption.At 7.76GHz,the CFO/RC-2 composite achieves an impressive minimum reflection loss(RL_(min))of-43.99 dB with a thickness of 2.44 mm.Moreover,CFO/RC-3 demonstrates an effective absorption bandwidth(EAB)of up to 4.16 GHz,accompanied by a thickness of 1.18mm.This study revealed the remarkable capability of the composite to diminish electromagnetic waves,providing a new generation method for microwave absorbing materials of superior quality. 展开更多
关键词 coal gasification slag residual carbon hydrothermal method microwave absorption CoFe_(2)O_(4)
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Fe_(3)O_(4)@SiO_(2)磁性吸附剂的制备及其对Er(Ⅲ)和Ho(Ⅲ)的吸附性能
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作者 周键 昝苗苗 +1 位作者 肖燕飞 刘嘉铭 《江西冶金》 2024年第1期53-57,共5页
稀土资源的开采伴随着稀土离子排放,对水资源造成了严重污染。吸附法是处理水相稀土离子污染的一种高效技术,磁性吸附剂能够加速固液分离,具有较大的研究价值。本研究以FeCl_(3)·6H_(2)O、甘醇、醋酸钠、聚乙二醇(PEG2000)等为原料... 稀土资源的开采伴随着稀土离子排放,对水资源造成了严重污染。吸附法是处理水相稀土离子污染的一种高效技术,磁性吸附剂能够加速固液分离,具有较大的研究价值。本研究以FeCl_(3)·6H_(2)O、甘醇、醋酸钠、聚乙二醇(PEG2000)等为原料,采用溶剂热法在200℃的条件下制备粒径约为230 nm的Fe_(3)O_(4)磁性纳米颗粒,将其加入正硅酸乙酯中,利用氨水水解聚合,即可形成粒径约为300 nm的Fe_(3)O_(4)@SiO_(2)磁性吸附剂材料。此复合材料为核壳结构,包含Fe_(3)O_(4)和SiO_(2)两种晶型结构。SiO_(2)的包覆未对Fe_(3)O_(4)物相结构产生较大影响,在包覆的同时能够显现出一定的磁性性能。此复合材料对Er(Ⅲ)和Ho(Ⅲ)的最大吸附容量分别达到10.03 mg/g和5.25 mg/g。 展开更多
关键词 Fe_(3)O_(4)磁性纳米粒子 Fe_(3)O_(4)@SiO_(2) 核壳结构 Er(Ⅲ) Ho(Ⅲ)
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CoFe_(2)O_(4)/ZIF-9催化过一硫酸盐降解罗丹明B
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作者 刘文一 孙德栋 +3 位作者 马红超 马春 郝军 张新欣 《大连工业大学学报》 CAS 2024年第3期167-171,共5页
采用共沉淀法成功合成了磁性CoFe_(2)O_(4)/ZIF-9复合材料。以罗丹明B溶液为污染物模型,通过催化剂催化过一硫酸盐评价其催化活性。催化剂筛选结果表明,复合催化剂CoFe_(2)O_(4)与ZIF-9的摩尔比为1∶5为最佳配比。实验结果表明,在20 min... 采用共沉淀法成功合成了磁性CoFe_(2)O_(4)/ZIF-9复合材料。以罗丹明B溶液为污染物模型,通过催化剂催化过一硫酸盐评价其催化活性。催化剂筛选结果表明,复合催化剂CoFe_(2)O_(4)与ZIF-9的摩尔比为1∶5为最佳配比。实验结果表明,在20 min内,用100 mg/L的PMS和50 mg/L的催化剂对罗丹明B的去除率为99.7%。CoFe_(2)O_(4)/ZIF-9复合材料具有制备简单、催化活性高、可重复使用、回收容易等优点,是修复水污染的高效催化剂。 展开更多
关键词 ZIF-9 铁酸钴 金属有机框架材料 过一硫酸盐 罗丹明B
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CoFe_(2)O_(4)-Al_(2)O_(3)复合材料的制备及其在含日落黄废水处理中的应用
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作者 尹大川 刘嘉润 +2 位作者 何怡静 乔宇 梁杰 《上海师范大学学报(自然科学版中英文)》 2024年第1期44-54,共11页
制备了铁酸钴-氧化铝(CoFe_(2)O_(4)-Al_(2)O_(3))复合材料,并采用扫描电子显微镜(SEM)、X射线衍射(XRD)、比表面积和孔径分析仪对多孔CoFe_(2)O_(4)-Al_(2)O_(3)复合材料的物相和形貌进行了分析.利用制备的CoFe_(2)O_(4)-Al_(2)O_(3)... 制备了铁酸钴-氧化铝(CoFe_(2)O_(4)-Al_(2)O_(3))复合材料,并采用扫描电子显微镜(SEM)、X射线衍射(XRD)、比表面积和孔径分析仪对多孔CoFe_(2)O_(4)-Al_(2)O_(3)复合材料的物相和形貌进行了分析.利用制备的CoFe_(2)O_(4)-Al_(2)O_(3)复合材料活化过硫酸氢钾(PMS)来降解废水溶液中的日落黄(SY),通过研究CoFe_(2)O_(4)-Al_(2)O_(3)材料制备过程中Co^(2+),Fe^(3+)和Al^(3+)的物质的量之比、煅烧温度和时长对材料催化性能的影响,发现Co^(2+),Fe^(3+)和Al^(3+)的最佳物质的量之比为1∶2∶12,最佳煅烧温度为400℃和最佳煅烧时长为3 h.对采用在最优条件下制得的CoFe_(2)O_(4)-Al_(2)O_(3)复合材料作为催化剂,PMS氧化降解含日落黄废水进行研究,考察了pH值、温度、不同体系、PMS用量、CoFe_(2)O_(4)-Al_(2)O_(3)材料用量和一些阴离子对日落黄降解的影响.结果表明:在pH=7,温度为55℃条件下,用0.1 g催化剂和0.125 g PMS能使100 mL质量浓度为0.6 g·L^(-1)的日落黄溶液在30 min内降解率达到99.5%.同时,碳酸氢根负离子(HCO3-)和硝酸根负离子(NO_(3)^(-))的加入抑制了日落黄的降解,而Cl^(-)则能促进日落黄的降解.此外,在进行4次循环使用后,CoFe_(2)O_(4)-Al_(2)O_(3)仍表现出很好的催化性能,日落黄去除效果仍能达到90%以上. 展开更多
关键词 铁酸钴-氧化铝(CoFe_(2)O_(4)-Al_(2)O_(3))复合材料 过硫酸氢钾(PMS) 日落黄(SY) 降解
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铁磁氧化物CoFe_2O_4的电子结构
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作者 宗波 曹青松 《天水师范学院学报》 2011年第5期32-34,共3页
CoFe_2O_4是一种具有半金属性和亚铁磁性的新型尖晶石结构材料,具有制备简单、居里温度高、室温自旋极化率大、高的饱和磁化强度和磁晶各向异性等优点.文中采用第一性原理计算方法对CoFe_2O_4结构进行了研究.通过对CoFe_2O_4的态密度分... CoFe_2O_4是一种具有半金属性和亚铁磁性的新型尖晶石结构材料,具有制备简单、居里温度高、室温自旋极化率大、高的饱和磁化强度和磁晶各向异性等优点.文中采用第一性原理计算方法对CoFe_2O_4结构进行了研究.通过对CoFe_2O_4的态密度分析得到:CoFe_2O_4晶体的轨道贡献主要来源于O原子的2p轨道,Fe原子的3d轨道和Co原子的3d轨道;CoFe_2O_4的半金属性主要是由于Co原子引起的;Fe原子和Co原子都具有较大的不同磁矩,而且方向相反,使得CoFe_2O_4具有亚铁磁有序. 展开更多
关键词 第一性原理 CoFe_2O_4 亚铁磁性 半金属性 电子结构
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“新工科”背景下生物制药专业多学科交叉融合的探索研究——以Fe_(3)O_(4)@SiO_(2)核壳磁性纳米粒子的制备及应用实验为例
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作者 相欣然 李文瑄 《广东化工》 CAS 2024年第5期164-167,共4页
“新工科”背景下,多学科交叉融合已成为生物制药专业教学育人的新方式,对培养“明德求真,弘药济世”的卓越应用型工程人才具有重要意义。本文将以Fe_(3)O_(4)@SiO_(2)核壳磁性纳米粒子的制备及应用实验为例,顺应教育部“三全育人”的... “新工科”背景下,多学科交叉融合已成为生物制药专业教学育人的新方式,对培养“明德求真,弘药济世”的卓越应用型工程人才具有重要意义。本文将以Fe_(3)O_(4)@SiO_(2)核壳磁性纳米粒子的制备及应用实验为例,顺应教育部“三全育人”的战略要求,在调动学生科研的积极性和主动性的同时,探索生物制药与有机化学之间的联系,挖掘多学科交叉融合的独特优势,提高学生的科学探究能力和实验操作能力。 展开更多
关键词 新工科 多学科交叉融合 纳米技术 Fe_(3)O_(4)@SiO_(2)核壳磁性纳米粒子 DNA提取
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Kinetics, thermodynamics, and equilibrium of As(Ⅲ),Cd(Ⅱ), Cu(Ⅱ) and Pb(Ⅱ) adsorption using porous chitosan bead-supported MnFe_(2)O_(4) nanoparticles 被引量:3
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作者 Hongxia Li Hongbing Ji +6 位作者 Xinglan Cui Xiaokui Che Qidong Zhang Juan Zhong Rongzhen Jin Lei Wang Yi Luo 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第6期1107-1115,共9页
A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(... A novel porous nanocomposite,cross-linked chitosan and polyethylene glycol(PEG) bead-supported MnFe_(2) O_(4) nanoparticles(CPM),was developed as an efficient adsorbent to remove metalloid(As(Ⅲ))and heavy metals(Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)).The characteristics of CPM showed a porous structure,well dispersed MnFe_(2) O_(4),and several of hydroxyl and amino groups(-OH,-NH_(2)).Batch experiments demonstrated that the best adsorption property of As(Ⅲ),Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ) was achieved within 8 h with maximum adsorption capacities of 9.90,9.73,43.94,and 11.98 mg/g,respectively.Competitive and synergistic effects(particularly precipitation) were included in the co-adsorption mechanism of As(Ⅲ) and heavy metals.Thereinto,As(Ⅲ) was partly oxidized by MnFe_(2) O_(4) to As(V),and both were coordinated on MnFe_(2) O_(4) nanoparticles.Pb(Ⅱ) could also bind to MnFe_(2) O_(4) by ion exchange and electrostatic attraction.Furthermore,Cd(Ⅱ) and Cu(Ⅱ) tended to be coordinated on chitosan.Therefore,CPM can serve as a remediation material for water and soil co-contaminated with As(Ⅲ) and heavy metals. 展开更多
关键词 EQUILIBRIUM ADSORPTION ARSENIC Cadmium CHITOSAN MnFe_(2)O_(4)nanoparticles
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Conductivity Study of Polyaniline-Cobalt Ferrite(PANI-CoFe_2O_4) Nanocomposite 被引量:2
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作者 E.E.Tanriverdi A.T.Uzumcu +2 位作者 H.Kavas A.Demir A.Baykal 《Nano-Micro Letters》 SCIE EI CAS 2011年第2期99-107,共9页
In this investigation,the structural and electrical properties of nanocomposites of polyaniline(PANI) and cobalt ferrite synthesized by hydrothermal route are reported for the first time(with weight ratios of CoFe_2O_... In this investigation,the structural and electrical properties of nanocomposites of polyaniline(PANI) and cobalt ferrite synthesized by hydrothermal route are reported for the first time(with weight ratios of CoFe_2O_4/PANI 1:2 and 2:1).Synthesized nanomaterials have been characterized by XRD,FT-IR,SEM and TEM techniques.FT-IR results confirm the presence of CoFe_2O_4 and PANI in the samples.Their detailed conductivity measurements have been investigated.It has been found that PANI has a more effective conducting mechanism in CoFe_2O_4-PANI composites.These results are also consistent with the change in AC conductivity orders in composites. 展开更多
关键词 CoFe_2O_4/PANI Hydrothermal Nanomaterials PERMITTIVITY MAGNETISM
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Development of an Amperometric Hydrogen Peroxide Biosensor based on the Immobilization of Horseradish Peroxidase onto Nickel Ferrite Nanoparticle-Chitosan Composite 被引量:2
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作者 Furkan Yalcner Emre Cevik +1 位作者 Mehmet Senel Abdulhadi Baykal 《Nano-Micro Letters》 SCIE EI CAS 2011年第2期91-98,共8页
Nickel ferrite(NiFe_2O_4) nanoparticles have been dispersed in chitosan solution in order to fab ricate nanocomposite films.Horseradish peroxidase(HRP) has been immobilized onto this chitosan NiFe_2O_4 nanocomposite f... Nickel ferrite(NiFe_2O_4) nanoparticles have been dispersed in chitosan solution in order to fab ricate nanocomposite films.Horseradish peroxidase(HRP) has been immobilized onto this chitosan NiFe_2O_4 nanocomposite film via physical adsorption.The size of the NiFe_2O_4 nanoparticles has been estimated us ing X ray diffraction pattern and scanning electron microscopy(SEM) to be 40±9 nm.The chitosan NiFe_2O_4 nanocomposite film and HRP/chitosan NiFe_2O_4 bioelectrode have been characterized using SEM technique.The HRP/chitosan NiFe_2O_4 nanocomposite bioelectrode has a response time of 4 s,linearity as 0.3 to 12 m M of H2O2,sensitivity as 22 n A/m M.The effects of p H and the temperature of the immobilized HRP electrode have also been studied. 展开更多
关键词 BIOSENSOR NiFe_2O_4 Horseradish peroxidase nanoparticle CHITOSAN
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Monodisperse polar NiCo_(2)O_(4) nanoparticles decorated porous graphene aerogel for high-performance lithium sulfur battery 被引量:1
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作者 Xiaohui Tian Yingke Zhou +2 位作者 Bingyin Zhang Naomie Beolle Songwe Selabi Guiru Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第11期239-251,I0008,共14页
Lithium sulfur battery(LSB)is a promising energy storage system to meet the increasing energy demands for electric vehicles and smart grid,while its wide commercialization is severely inhibited by the"shuttle eff... Lithium sulfur battery(LSB)is a promising energy storage system to meet the increasing energy demands for electric vehicles and smart grid,while its wide commercialization is severely inhibited by the"shuttle effect"of polysulfides,low utilization of sulfur cathode,and safety of lithium anode.To overcome these issues,herein,monodisperse polar NiCo_(2)O_(4)nanoparticles decorated porous graphene aerogel composite(NCO-GA)is proposed.The aerogel composite demonstrates high conductivity,hierarchical porous structure,high chemisorption capacity and excellent electrocatalytic ability,which effectively inhibits the"shuttle effect",promotes the ion/electron transport and increases the reaction kinetics.The NCO-GA/S cathode exhibits high discharge specific capacity(1214.1 mAh g^(-1)at 0.1 C),outstanding rate capability(435.7 mAh g^(-1)at 5 C)and remarkable cycle stability(decay of 0.031%/cycle over 1000 cycles).Quantitative analyses show that the physical adsorption provided by GA mainly contributes to the capacity of NCO-GA/S at low rate,while the chemical adsorption provided by polar NiCo_(2)O_(4)contributes mainly to the capacity of NCO-GA/S with the increase of current density and cycling.This work provides a new strategy for the design of GA-based composite with synergistic adsorption and electrocatalytic activity for the potential applications in LSB and related energy fields. 展开更多
关键词 Porous graphene aerogel Monodisperse nanoparticles Polar NiCo_(2)O_(4) Chemical adsorption Catalytic conversion Lithium sulfur battery
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Covalent immobilization and characterization of Rhizopus oryzae lipase on core-shell cobalt ferrite nanoparticles for biodiesel production
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作者 Saboura Ashkevarian Jalil Badraghi +2 位作者 Fatemeh Mamashli Behdad Delavari Ali Akbar Saboury 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第9期128-136,共9页
Rhizopus oryzae lipase(ROL)was immobilized on the surface of silica coated amino modified CoFe_(2)O_4 nanoparticles and applied for biodiesel production.The results indicated more affinity of the ROL toward its substr... Rhizopus oryzae lipase(ROL)was immobilized on the surface of silica coated amino modified CoFe_(2)O_4 nanoparticles and applied for biodiesel production.The results indicated more affinity of the ROL toward its substrate upon immobilization,as revealed by a lower Km value for the immobilized ROL compared to its free counterpart.Intrinsic fluorescence spectroscopy indicated a lower intensity for ROL immobilized on CoFe_(2)O_4 nanoparticles.Besides,immobilized ROL steady state anisotropy measurements presented lower values,which implied assembly of ROL molecules on magnetic nanoparticles upon immobilization as well as their restricted rotation upon covalent attachment.Thermal stability analysis revealed improved activity at higher temperatures for the immobilized enzyme compared to its free counterpart.Accordingly,Pace analysis to determine protein thermal stability revealed preservation of the protein conformation in the presence of increasing temperatures upon immobilization on nanoparticles.Finally,ROL immobilized on CoFe_(2)O_(4)nanoparticles exhibited improved efficiency of biodiesel production in agreement with thermal activity profile.Therefore,the authors suggest application of the lipase molecules immobilized on CoFe_(2)O_(4)nanoparticles for more efficient biodiesel production. 展开更多
关键词 Lipase immobilization CoFe_(2)O_(4)magnetic nanoparticles Steady state anisotropy BIODIESEL BIOCATALYSIS Protein stability
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FERROMAGNETIC RESONANCE STUDIES OF Co/CoFe_2O_4 MULTILAYERS
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作者 B.X. Gu(Department of Physics, Nanjing University, Nanjing 210093, China)H. Wang(Department of Physics, Southeastern University, Nanjing 210008, China)Manuscript receivedin revised form 12 October 1998) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第2期181-184,共4页
The Co/CoFe2O4 multilayers have been grown on the glass substrate using sputtering techniques. In these films the Co layers were measured to have the fcc structure with [11] axis perpendicular to the film plane, and t... The Co/CoFe2O4 multilayers have been grown on the glass substrate using sputtering techniques. In these films the Co layers were measured to have the fcc structure with [11] axis perpendicular to the film plane, and the CoFe2O4 layers are amorphous. Ferromagnetic resonance measurements have been made as a function of the external magnetic field orientation in a plane perpendicular to the film. The effective magnetization, effective anisotropy constant and interface anisotropy constant have been determined. The influence of Co layers thickness on magnetic properties was discussed. 展开更多
关键词 Co/CoFe_2O_4 multilayer ferromagnetic resonance magnetic property
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Electronic structure modulation with ultrafine Fe_(3)O_(4) nanoparticles on 2D Ni-based metal-organic framework layers for enhanced oxygen evolution reaction
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作者 Wei Huang Chao Peng +7 位作者 Jing Tang Fangyuan Diao Murat Nulati Yesibolati Hongyu Sun Christian Engelbrekt Jingdong Zhang Xinxin Xiao Kristian S.Mølhave 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第2期78-88,共11页
Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanopart... Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite. 展开更多
关键词 Fe_(3)O_(4)nanoparticles 2D Ni-BDC Aggregation Electronic structure modulation Oxygen evolution reaction
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Preparation of novel magnetic nanoparticles as draw solutes in forward osmosis desalination
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作者 Dongze Ma Ye Tian +1 位作者 Tiefei He Xiaobiao Zhu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第6期223-230,共8页
Novel magnetic nanoparticles(MNPs),Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2),were prepared by loading different amounts of SiO_(2) or/and PEG-(COOH)_(2) onto Fe_(3)O_(4) nanoparticles,and their feasib... Novel magnetic nanoparticles(MNPs),Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2),were prepared by loading different amounts of SiO_(2) or/and PEG-(COOH)_(2) onto Fe_(3)O_(4) nanoparticles,and their feasibility to be used as forward osmosis(FO)draw solutes was investigated.The characterization of the materials showed that,compared to normal Fe_(3)O_(4) nanoparticles,the modified MNPs exhibited enhanced dispersity and high osmotic pressure in aqueous solution.The FO experiment indicated that the synthesized draw solutes could obtain a water flux as high as 10 L·m^(-2)·h^(-1) with an aquaporin FO membrane.The optimal concentration of the added tetraethyl orthosilicate was 30%during the synthesis.The novel MNPs could be easily recovered from draw solutions by magnetic field,and the recovery rate of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was 83.95%and 63.37%,respectively.Moreover,after 5 recycles of reuse,the water flux of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) as draw solutes still remained 64.36%and 85.26%,respectively.The experimental results demonstrated that the synthesized core–shell magnetic nanoparticles are promising draw solutes,and the Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was more suitable to be used as draw solute in FO process. 展开更多
关键词 Magnetic nanoparticles Forward osmosis Draw solute Fe_(3)O_(4) PEG-(COOH)_(2)
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CoFe_(2)O_(4)/MCM-41催化剂的制备及其光催化降解亚甲基蓝性能 被引量:2
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作者 田志茗 常悦 《石油化工》 CAS CSCD 北大核心 2023年第2期154-160,共7页
采用水热法将纳米CoFe_(2)O_(4)与MCM-41介孔分子筛复合,制备了CoFe_(2)O_(4)/MCM-41光催化剂。通过TG-DTA,XRD,SEM,N2吸附-脱吸等方法对制备的催化剂进行表征,并以亚甲基蓝染料废水为研究对象,考察了催化剂光催化降解亚甲基蓝的性能。... 采用水热法将纳米CoFe_(2)O_(4)与MCM-41介孔分子筛复合,制备了CoFe_(2)O_(4)/MCM-41光催化剂。通过TG-DTA,XRD,SEM,N2吸附-脱吸等方法对制备的催化剂进行表征,并以亚甲基蓝染料废水为研究对象,考察了催化剂光催化降解亚甲基蓝的性能。实验结果表明,CoFe_(2)O_(4)/MCM-41催化剂仍具有介孔材料的孔道结构,CoFe_(2)O_(4)纳米粒子在分子筛孔道或表面均匀分散,呈现尖晶石结构,使CoFe_(2)O_(4)/MCM-41复合催化剂具有良好的催化活性。CoFe_(2)O_(4)/MCM-41复合催化剂(Co与Si摩尔比为1∶1)在初始染料质量浓度为10 mg/L、溶液pH=7、可见光照射的条件下,2 h内对亚甲基蓝降解率达到98.3%,降解速率符合一级反应动力学。CoFe_(2)O_(4)/MCM-41重复使用5次后,亚甲基蓝的降解率仍可达到86.6%。 展开更多
关键词 CoFe_(2)O_(4)/MCM-41 光催化 降解 亚甲基蓝
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复合光催化剂CoFe_(2)O_(4)/BiVO_(4)/电气石的超声-光催化研究 被引量:1
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作者 张进治 谢亮 《材料导报》 EI CAS CSCD 北大核心 2023年第6期61-66,共6页
以电气石为载体,采用水热法原位生长BiVO_(4)、CoFe_(2)O_(4),得到CoFe_(2)O_(4)/BiVO_(4)/电气石复合光催化剂,利用XRD、SEM、EDS、UV-Vis DRS等方法对材料进行了表征,通过降解灿烂绿对样品的声光催化性能进行评价。结果表明,在60 min... 以电气石为载体,采用水热法原位生长BiVO_(4)、CoFe_(2)O_(4),得到CoFe_(2)O_(4)/BiVO_(4)/电气石复合光催化剂,利用XRD、SEM、EDS、UV-Vis DRS等方法对材料进行了表征,通过降解灿烂绿对样品的声光催化性能进行评价。结果表明,在60 min可见光下,BiVO_(4)对灿烂绿的降解率为33.5%,CoFe_(2)O_(4)(10%)/BiVO_(4)(45%)/电气石对灿烂绿的降解率为74%;在60 min可见光+超声下,BiVO_(4)对灿烂绿的降解率为61.5%,CoFe_(2)O_(4)(10%)/BiVO_(4)(45%)/电气石在声光作用下(12 min内)对灿烂绿的降解率高达99.2%。高效的降解率可能与复合结构的异质结有关,CoFe_(2)O_(4)/BiVO_(4)/电气石对可见光的吸收能力得到提高,促进了光生电子-空穴的分离,从而有效增强光降解性能。另外,从超声+光催化的效果可看出超声协同光催化降解效果显著。声光催化在有机污染物降解领域内的应用成为一个重要研究方向,如能结合彼此优点,可望开发出高效实用的催化材料。 展开更多
关键词 复合光催化剂 超声-光催化 铁酸钴/钒酸铋/电气石
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