中空钴酸镍纳米微球的制备及电化学性能研究

以碳微球为模板,通过溶剂热法及随后的煅烧处理得到中空的NiCo_2O_4纳米微球,通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品的组成及形貌进行了表征。结果表明,制备的NiCo_2O_4中空微球具有高度的结晶性,粒径为300 nm,空心球壁厚为30 nm,当用作锂离子电池负极材料时,在1 000 mA/g电流密度下,首次放电容量达到了1 360 mA/hg,循环250次后,容量仍然高达585 mA/hg,库伦效率高达99%,表现出了优异的循环性能。     

中空ZnFe2O4微球的合成及其电化学性能

以Zn(Ac)2×4H2O和FeCl3×6H2O为主要原料,采用一步水热法合成了中空结构的ZnFe2O4微球,对其物相、形貌和组成进行了分析. 结果表明,中空ZnFe2O4粒径微球约300 nm,壳厚约25 nm. 以其为锂离子电池负极材料,100 mA/g电流密度下,首次放电容量为1524 mA×h/g, 50次充放电循环后容量约为826 mA×h/g,呈现出优异的循环性能.     

SnO2纳米球的制备、结构及电化学性能研究

以Na2SnO3.4H2O为原料,CO(NH2)2为表面活性剂,采用水热法制备了SnO2纳米球。利用X射线衍射（XRD)、扫描电子显微镜（SEM)、比表面积测试仪（BET）及电化学测试仪等研究材料的结构、形貌、比表面积及电化学性能。结果表明,制备的SnO2材料具有较好的球体形貌,颗粒分散均匀,形状规准,半径约为400 nm,结构呈典型的金红石相。在电压范围为0.01~3 V, 200 mA/g的电流密度下进行充放电测试,首次放电比容量为2206.6 mAh/g,50次循环后,放电比容量保持在440 mAh/g,具有较好的循环性能。     

SnO_2纳米球的制备及其电化学性能

以Na_2SnO_3·4H_2O为原料,CO(NH_2)_2为沉淀剂,采用水热法制备了SnO_2纳米球。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、比表面积测试仪(BET)及电化学测试仪测试材料的结构、形貌、比表面积及电化学性能。结果表明,所制备的纳米SnO_2材料具有规整的球体形貌,颗粒分散均匀,半径约为400nm,呈典型的金红石相结构。在电压为0.01~3V、电流密度200mA/g的条件下进行充放电测试,首次放电比容量为2206.6mA·h/g,50次循环后,放电比容量保持在440mA·h/g,具有较好的循环性能。     

纳米LiMn2O4制备及电化学性能研究

以高能球磨后的MnO2为前躯体,用水热法成功合成了平均粒径为60nm的LiMn2O4纳米微粒。实验结果表明,所合成的纳LiMn2O4在0．2℃倍率放电条件下,首次放电比容量为122mAh／g,样品在经过20次循环后容量下降约为5％左右,表现出较好的电化学性能。     

颗粒状钼酸镍负极材料的制备及其电化学性能

为了获得高性能锂离子电池负极材料,以NiCl2·6H2O和乙酰丙酮钼为原料,通过溶剂热法和高温热处理成功合成了颗粒状NiMoO4,将其用于锂离子电池负极材料。采用XRD、SEM、TEM、Raman、BET技术对NiMoO4进行了结构和形貌表征。结果表明,在100 mA/g的电流密度下循环250圈后,可逆容量高达829 mA·h/g。同时,颗粒状NiMoO4展现出了优异的倍率性能。当电流密度从100 mA/g增加到5000 mA/g,然后恢复到100 mA/g时,容量还能够维持恢复到原来的水平。另外,颗粒状NiMoO4电极在1000、 2000、5000 mA/g大电流下,其可逆容量还能够分别高达600、529和412 mA·h/g。     

TiO_2中空微球的制备及性能

以钛酸丁酯为钛源,采用无模板溶剂热法合成了Ti O_2中空微球,并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、N_2物理吸附-脱附(BET)对样品进行了表征和分析,以甲基橙为模拟污水考察了样品光催化降解甲基橙的能力。结果表明,Ti O_2中空微球为锐钛矿相,是由细小的纳米晶自组装形成的具有中空结构的Ti O_2微球,微球的直径为0.4~0.5μm,样品的比表面积为60 m~2/g。在8 W紫外灯照射下,将Ti O_2中空微球加到初始溶度为15 mg/L的甲基橙溶液中,在光照80 min后甲基橙降解率达到95%,表现出良好的光催化活性。     

TiO2中空微球的制备及性能研究

以钛酸丁酯为钛源,采用无模板法溶剂热合成了中空TiO2微球,并采用了X射线衍射(XRD)、扫描电镜(SEM)、透射电镜（TEM）、N2物理吸附-脱附（BET）等手段对样品进行了表征和分析,以甲基橙为模拟污水研究了样品光催化降解甲基橙的能力。结果表明, 中空TiO2微球为锐钛矿相,是由细小的纳米晶自组装组成的具有中空结构的TiO2微球,微球的直径为0.4~0.5 μm。样品具有介孔结构和较高的比表面积,在紫外光照射下,加入中空TiO2微球到初始溶度为15 mg/L的甲基橙溶液中,在光照80 min后降解甲基橙达到了95%,表现出良好的光催化活性。     

尖晶石锰酸锂纳米粒子的制备及其电化学性能研究

采用一种溶胶凝胶法制备尖晶石锰酸锂纳米粒子并对其恒电流充放电和交流阻抗特性进行了研究。结果表明,所制备的锰酸锂材料首次放电容量达到133 mAg/g,但经过5次充放电循环后容量的衰减率超过10％。容量衰减比较快的原因可能是由于所制备的纳米尖晶石锰酸锂材料表面积大,其与电解液的反应也比较快。     

TiNb2O7复合材料的制备及电化学性能

以聚偏氟乙烯为氟碳源,利用两步法合成了Ti Nb2O7@F-C复合材料。借助XRD、SEM、新威电池测试系统等进行表征分析。实验结果表明:当聚偏氟乙烯加入量为0.05 g时制得的Ti Nb2O7@F-C复合材料既能保持着多孔结构又有F掺杂碳包覆层,用作锂离子电池负极具有优异的电化学性能。     

MnO2纳米空心球的制备及其电化学性能

采用水热法通过添加Ce离子制备了MnO₂纳米空心球电极材料。Ce离子对MnO₂的形貌和结晶程度有很大的影响,添加Ce离子后生成由纳米棒组成的中空球,中空球比表面积(BET)达到315.2 m²·g^-1。MnO₂电极电化学测试结果表明:当铈锰摩尔比为0.2时电极材料具有较好的电化学性能,其比电容达到178.6 F·g^-1,与未加Ce离子相比其比电容提高了2.6倍,而且经过1000次循环稳定性测试后比电容仍保留了90.5%。这些结果表明添加Ce离子有利于形成中空结构,并提高了MnO₂电极的比电容。     

碳包覆空心Fe_3O_4纳米球的制备及其电磁波吸收特性研究

以六水合氯化铁为铁源,尿素为沉淀剂和软模板,乙二醇为溶剂,通过溶剂热法制备分散性良好且尺寸均匀的空心Fe_3O_4纳米颗粒,采用二次水热法制备核-壳结构的空心Fe_3O_4/C纳米颗粒。研究表明,空心状的Fe_3O_4纳米颗粒表面均匀地包覆了一层无定型碳层。相比单独的空心Fe_3O_4纳米颗粒,包碳后核壳结构的Fe_3O_4/C复合材料电磁波吸收性能显著增强。在匹配厚度仅为4.5 mm时,在11.6 GHz时,其最小反射损耗值可达到-25.2 d B,表现出良好的微波吸波特性。此类核-壳状Fe_3O_4/C磁性球在雷达波吸收、通讯领域等具有广泛的应用前景。     

碳包覆空心Fe_3O_4纳米球的制备及其电磁波吸收特性研究

以六水合氯化铁为铁源,尿素为沉淀剂和软模板,乙二醇为溶剂,通过溶剂热法制备分散性良好且尺寸均匀的空心Fe_3O_4纳米颗粒,采用二次水热法制备核-壳结构的空心Fe_3O_4/C纳米颗粒。研究表明,空心状的Fe_3O_4纳米颗粒表面均匀地包覆了一层无定型碳层。相比单独的空心Fe_3O_4纳米颗粒,包碳后核壳结构的Fe_3O_4/C复合材料电磁波吸收性能显著增强。在匹配厚度仅为4.5 mm时,在11.6 GHz时,其最小反射损耗值可达到-25.2 d B,表现出良好的微波吸波特性。此类核-壳状Fe_3O_4/C磁性球在雷达波吸收、通讯领域等具有广泛的应用前景。     

NiCo2O4/Ni复合电极的制备及电催化性能研究

采用共沉降法制备了以Ni为载体的NiCo2O4/Ni的电催化剂,分别用TG、XRD、SEM对NiCo2O4粉末的结构和形貌进行了表征,研究了不同温度下NiCo2O4/Ni复合电极在碱性水溶液中的催化性能.结果表明,热处理温度对NiCo2O4粉末的结构、电催化性能有重要的影响,当热处理温度为300%时NiCo2O4/Ni...     

Template-free synthesis of Cu2O hollow nanospheres and their conversion into Cu hollow nanospheres

In this paper, Cu₂O hollow nanospheres were first generated through a template free process, and then Cu hollow nanospheres were prepared using Cu₂O hollow nanospheres as precursor and H₂ as reductant. Phase identification and morphology observation of the products were carried out by X-ray diffraction(XRD), Transmission electron microscopy (TEM) and Field scanning electron microscopy (FSEM). The results show that Cu₂O nanospheres generated at reflux are porous and hollow both in absolute alcohol and tert-butyl alcohol. It is feasible to fabricate well-dispersed Cu hollow nanospheres from Cu₂O hollow nanospheres at 170 °C. Moreover, a remarkable blue shift effect was found in the ultraviolet-visible light (UV-visible) absorption spectra for both Cu₂O and Cu hollow nanospheres.     

Synthesis of stable hollow silica nanospheres

Hollow silica nanospheres with their size distribution ranging from 350 nm to 450 nm are synthesized by using polystyrene (PS) templates in the present study. On the basis of PS templates, silica, the hydrolyzate of TEOS(tetraethyl orthosilicate) under moist alkaline condition at ambient temperatures and atmospheric pressures, it is set to be coated on the surface of the PS spheres. Since the size of PS sphere core can be easily controlled, it is expected to serve various needs of different sized hollow silica nanospheres in industrial applications. It is proposed that the PS cores be removed by either thermal pyrogenation or solvent dissolved. Morphology of the hollow silica nanospheres is characterized by scanning electron microscopy (SEM).     

基于废旧锂离子电池正极材料LiMn2O4制备MnO2及其电化学性能

以废旧锂离子电池LiMn₂O₄正极材料为原料,通过控制酸浸条件分别制备出λ-MnO₂纳米粒子和β-MnO₂纳米棒,研究作为一次电池电极材料和超级电容器电极材料的相关电化学性能。利用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和恒电流充放电、循环伏安等测试手段对样品成分、形貌和电化学性能进行分析表征。实验表明：在常温常压下,采用0.5 mol·L^-1的H₂SO₄酸浸3 h可制备出λ-MnO₂纳米颗粒;而于相似文献   

Synthesis of multifunctional hollow SiO2-CaO-Fe2O3 glass-ceramic nanospheres

Glass ceramics with multifunctions of bioactivity, drug delivery, and magnetic hyperthermia have great potential applications in the field of bioscience. Herein, we design and synthesize a multifunctional hollow SiO₂-CaO-Fe₂O₃ (SCF) glass-ceramic nanosphere (GCNS) by a template-mediated sol-gel precipitate method. The magnetite as the main crystal phase was successfully precipitated from the SCF glassy matrixes after heat treated at 800°C. The influence of composition and the Fe³⁺/Fe²⁺ precursor ratio on the morphology, crystallization, micropore structure, and magnetic properties were systematically studied. Intact spherical hollow SCF GCNSs were obtained under the heat treatment at 800°C for 2 hours when the Fe₂O₃ content below 15 wt%. Under certain Fe₂O₃ content, the coercivity and micropore volume of SCF GCNSs were found to be increased with increasing the mole ratio of FeCl₃/FeCl₂ precursors. High drug loading capacity of 24.2 wt% and sustained drug release were observed from the methylene blue–loaded SCF GCNSs in simulated body fluid solution. The hollow SCF GCNSs synthesized in this work exhibiting good magnetic properties and sustained drug release performance have great potential applications in the cancer therapy.     

Synthesis of hollow carbon nano-onions and their use for electrochemical hydrogen storage

In this study, we report an efficient method for synthesis of well-graphitized hollow carbon nano-onions (CNOs). CNOs were firstly fabricated by chemical vapor deposition (CVD) method at 850 °C using an Fe–Ni alloy catalyst with diameters of 10–15 nm. Then hollow CNOs were obtained by annealing as-prepared CNOs at 1100 °C for 3 h. It is found that during the CVD growth, the presence of nickel retards the deactivation of Fe–Ni–C austenite, providing the possibility for the growth of up to two hollow CNOs from each alloy particle. The subsequent high-temperature annealing led to the escaping of the Fe–Ni alloy from the graphitic layers, and the re-catalysis of precipitation and graphitization of the carbon atoms previously dissolved in the alloy particle (Fe_0.64Ni_0.36) to form hollow CNOs. The hollow CNOs exhibit good performance as materials for electrochemical hydrogen storage, with a discharge capacity of 481.6 mAh/g under a current density of 500 mA/g, corresponding to a hydrogen storage capacity of 1.76 wt.%. Our results demonstrate that the hollow CNOs are promising materials as a storage medium for hydrogen as a fuel source.