溶胶-凝胶法制备尖晶石结构镍锰氧化物型锂离子筛

采用溶胶-凝胶法,以乙酸锂、乙酸镍和乙酸锰为主要原料,通过正交试验得到制备镍锰氧化物型锂离子筛LiNixMn2-xO4的适宜条件:x=0.05,柠檬酸作螯合剂,焙烧温度700℃,焙烧时间8 h。用0.5 mol.L-1过硫酸铵作抽锂剂,Mn2+的溶出率较低,仅为0.31%。通过X射线衍射分析证明所合成的锂离子筛为尖晶石结构,每克离子筛对Li+的饱和交换容量达36.72 mg。     

离子掺杂和碳修饰对Li_2FeSiO_4结构和性能的影响

采用高温固相反应方法合成锂离子电池正极Li_2Fe_(1-x-y)Mn_xNi_ySiO_4/C复合材料,并采用X-ray线衍射、扫描电子显微镜和电化学分析方法,研究了Ni和Mn离子共掺杂及碳修饰复合改性对复合材料结构和性能的影响。结果表明,复合改性没有对材料的晶体结构造成改变,镍锰离子共掺杂和表面碳包覆能有效提高材料的比容量和循环性能;以C/32倍率充放电,复合掺杂得到的Li_2Fe_(0.6)Mn_(0.2)Ni_(0.2)SiO_4/C材料样品的电化学性能最优,根据实测结果,该复合材料的首次放电比容量达到149 m Ah·g~(-1),充放电循环10次以后容量保持率仍有95.3%。     

Synthesis of Li2Fe0.9Mn0.1SiO4/C composites using glucose as carbon source

Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using glucose as carbon source. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% (mass fraction), the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent the capacity retention remains 92.2% after 30 cycles.     

TiO_2/ZnO/Ni_(0.5)Zn_(0.5)Fe_2O_4磁载光催化剂的制备及其光催化性能

采用均匀沉淀法制备了镍锌铁氧体、纳米TiO2-ZnO复合粉体和镍锌铁氧体负载纳米TiO2-ZnO复合粉体,并用XRD对所制粉体进行了表征。发现所制得的纳米TiO2为锐钛矿型、镍锌铁氧体为尖晶石型。以甲基橙溶液为模拟废水,考察了纳米TiO2-ZnO复合粉体和镍锌铁氧体负载纳米TiO2-ZnO复合粉体的光催化活性。研究还发现镍锌铁氧体负载纳米TiO2-ZnO粉体后仍具有良好的磁性能,可通过增加外磁场进行分离。     

溶胶-凝胶法制备 Ni0.5Zn0.5Fe2O4纳米材料特性的研究

利用溶胶．凝聚法制备了Ni0.5Zn0.5Fe2O4粉末材料,烧结温度范围600℃-950℃。对材料的结构、红外、磁学和微波吸收特性进行了研究。材料的XRD图谱和原子力显微镜形貌观察表明,材料在纳米尺度范围之内。在500cm-1--600cm-1波数范围内,材料具有明显的红外吸收特性。材料的晶粒尺寸随着烧结温度的提高而增加,且较高温度烧结的材料具有相对低的矫顽力和饱和磁场。利用反射衰减实验研究材料在6GHz--10GHz波段范围的吸波特性,结果表明,0．33mm厚度的样品在常温下的反射衰减达到1．8dBm。     

Mg0.5La0.5MnxAl12-xO19的甲烷纯氧燃烧催化行为研究

采用溶胶凝胶法,以柠檬酸为络合剂,合成了Mg0.5La0.5MnxAl12-xO19(x=0,1,2,3)系列六铝酸盐催化剂,用XRD对样品结构进行了分析,考察Mn的掺量对样品相结构的影响;采用固定床反应器,考察了在纯氧条件下催化剂的甲烷催化燃烧的活性.实验结果表明:采用溶胶凝胶法制备的Mn离子掺杂样品均能形成六铝酸盐相;在550℃,Mn离子能显著提高六铝酸盐的甲烷纯氧燃烧催化能力.     

(Li_(0.5)Fe_(0.5))_(0.7-y)Zn_(0.3)C_(oy)Fe_2O_4铁氧体磁性的研究

在Li－Zn铁氧体（Li0.5Fe0.5）0.7ZnFe2O4基础上,用Co2 离子代换其中的（Li Fe3 ）0.5离子,研究了（Li0.5Fe0．5）0.7－yZn0.3CoyFe2O4（y＝0．00;0．005;0．01;0．02;0．03）铁氧体磁性与Co2 离子代换换量y之间的关系,结果表明：随着Co2 离子代换量的增大,晶格常数增大,而气隙率及居里温度减小,当代换量y＜0．005时,饱和磁性极化强度增大。     

溶胶-凝胶法制备超细氧化铁的工艺研究

文中以柠檬酸为络合剂,用溶胶-凝胶法制备超细Fe2O3粉,并用TG／DTA对干凝胶进行了热分析,用XRD、SEM对产物的粒度及分散性进行了表征;考察了无水乙醇,乙二醇及金属离子与柠檬酸摩尔比对产物粒度、形貌及分散性的影响。结果表明：柠檬酸溶胶-凝胶法制备的Fe2O3的粒度比醇盐法的要细,乙二醇的加入能够减轻产物的团聚现象,当金属离子与柠檬酸的摩尔比为1：1时,产物的粒度和分散性最佳,XRD测出原始晶粒的精确尺寸为18．3nm,SEM所测团粒的平均粒径为200nm左右,且颗粒近似球形．     

Fabrication and characterization of highly ordered Ni0.5Zn0.5Fe2O4 nanowire/tube arrays by sol-gel template method

Highly ordered nanowire/tube arrays of Ni0.5Zn0.5Fe2O4 were fabricated by the sol-gel method in the pores of anodic alu- mina membrane (AAM). Whether nanowires or nanotubes were fabricated depends on immersion time. The immersion time was 15-40 s for nanotubes and over 60 s for nanowires. The topography and crystalline structure of the nanowire arrays were character- ized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). It was found that the length and diameter of the Ni0.5Zn0.5Fe2O4 nanowires are related to the thickness of the AAM and the diameter of the pores. The results indicated that the Ni0.5Zn0.5Fe2O4 nanowires are uniform and parallel to each other.     

LaCoO3掺杂Ba和Fe催化分解NO的研究

采用柠檬酸溶胶-凝胶法合成了La(Ba)Co(Fe)O3钙钛矿型氧化物催化剂,通过XPS、XRD、H2-TPR、FT-IR、BET等表征手段考察了催化剂分解NO的催化活性.结果表明,LaCoO3的A位掺杂适量Ba可以提高催化剂表面的氧空位浓度,La0.8 Ba0.2CoO3的B位掺杂Fe,活化了Co-O键,产生协同作用,提高了分解NO的催化活性.     

NaHSO_4·SiO_2催化制备生物柴油的研究

以NaHSO4·H2O、正硅酸乙酯和异丙醇为原料,经溶胶—凝胶法制备固体酸催化剂（NaHSO4·SiO2）,进行了利用此催化剂催化油酸与甲醇的酯化反应制备生物柴油的实验,研究了催化剂焙烧温度、NaHSO4负载量、反应时间、催化剂质量分数、甲醇与油酸物质的量比等对油酸转化率的影响。实验结果表明：固体酸催化剂NaHSO4·SiO2在油酸与甲醇的酯化反应中具有很高的催化活性,当催化剂焙烧温度为200℃、NaHSO4负载量为15%、n（甲醇）∶n（油酸）=10∶1、催化剂质量占油酸质量的10%、反应时间5h时,酯化反应转化率可达95.19%。     

高岭土掺杂NASICON固体电解质及全固态电池性能

针对LiTi2(PO4)3基固态电解质电导率低的问题,采用浙江三门高岭土矿作为主要原料,以高温固相法制备铝、镁、硅共掺杂钠超离子导体(NASICON)型快离子导体Li1+2x+2yAlxMgyTi2-x-ySixP3-xO12.研究掺杂比例、温度对固态电解质离子电导率的影响.结果表明,组成为Li1.8Al0.1Mg0.3Ti1.6Si0.1P2.9O12固体电解质在423 K时有最高离子电导率7.86×10-4 S·cm-1.以该组成固态电解质为基片,喷雾热解原位制备Al/ Li1+xV3O8/ Li1.8Al0.1Mg0.3Ti1.6Si0.1 P2.9O12 /C全固态电池并在1.8～3.9 V电压区间进行50次充放电测试.该电池具有较好的稳定性及循环容量保持能力.30次循环以后放电容量基本稳定在190～205 mAh·g-1之间,充放电效率大于90%.     

Er~(3+)∶Y_(0.5)Gd_(0.5)VO_4晶体生长和基本特性

Er3+∶Y0.5Gd0.5VO4晶体作为一种新的激光材料,可以用中频感应加热提拉法生长。X射线衍射分析表明,它的结构与Er3+∶GdVO4晶体结构相同,它的晶格常数介于GdVO4和YVO4晶格常数之间。用ICP光谱法测定晶体中Er3+离子分凝系数为1.06;采用稳态纵向热流法测出晶体c轴的热导率为7.2 W.m-1.k-1。     

γ-LiAlO2:Tb3+绿色荧光粉制备及其发光性能

采用柠檬酸溶胶-凝胶法合成了γ-LiAlO2:Tb3+绿色荧光粉,研究了材料的激发和发射光谱。γ-LiAlO2:Tb3+材料呈多峰发射,发射峰位于489、542、584和620 nm,分别对应于Tb3+的5D4→7FJ,J=6,5,4,3跃迁发射,主峰位于542 nm。监测542 nm发射峰,荧光体的最大激发峰位于238 nm,属于宽带激发。研究了Tb3+掺杂浓度及电荷补偿剂Li+对γ-LiAlO2:Tb3+材料发射强度的影响。结果表明:调节激活剂浓度、添加电荷补偿剂(Li+)均可以在很大程度上提高材料的发射强度。     

Structure and electrochemical properties of LiLaxMn2-xO4 cathode material by the ultrasonic-assisted sol-gel method

Powders of spinel LiLaxMn2_xO4 were successfully synthesized by the ultrasonic-assisted sol-gel (UASG) method.The structure and properties of LiLaxMn2_xO4 were examined by X-ray diffraction (XRD),Fourier transform infrared (FT-IR) spectros-copy,scanning electronic microscopy (SEM),galvanostatic charge-discharge test,and cyclic voltammetry (CV).XRD results showthat the La3+ can partially replace Mn3+ in the spinel and the doped materials with La3+ have a larger lattice constant compared with pristine LiMn2O4.FT-IR indicates that the absorption peak of Mn3+-O and Mn4+-O bonds has a red and blue shift with the increase of doping lanthanum in LiLaxMn2_xO4,respectively.The charge-discharge test exhibits that the initial discharge capacity of LiLaxMn2_xO4 drops off,and the capacity retention increases gradually at C/5 discharge rate with the increase of doping lanthanum,and LiLa0.01Mn1.99O4 has a higher discharge capacity and a better cycling performance at 1C discharge rate.CV reveals that the dop-ing La3+ is beneficial to the reversible extraction and intercalation of Li+ ions.     

(Na_(0.5)K_(0.5))NbO_3基无铅压电陶瓷压电常数的研究

针对目前无铅压电陶瓷的压电常数d33偏小的情况,采用传统的烧结方法制备了(Na0.5K0.5)NbO3基无铅压电陶瓷(Na0.5K0.45Li0.05)Nb0.95-xSbxTa0.05O3(x=0.03,0.06,0.09,0.12),研究了在Li和Ta含量固定的情况下,Sb元素的添加量和烧结温度对陶瓷的压电常数的影响.研究结果表明,适量Sb元素的掺杂可以大幅度提高陶瓷的压电常数d33,陶瓷样品的压电常数d33随着Sb含量的增加先增大后减小.烧结温度可以影响陶瓷的密度,进而影响其压电常数.在1130℃的最佳烧结温度下,Sb含量x=0.09时,陶瓷样品表现出最佳的压电性能,压电常数d33=328 pC/N.     

Li-Zn-Cu和Li-Zn-Co系铁氧体Mossbauer效应研究

在室温条件下,测量了多晶铁氧体（Ｌｉ０．５Ｆｅ０．５）０．７－ｘＺｎ０．３ＣｕｘＦｅ２Ｏ４（ｘ＝０．０;０．０３;０．０５;０．０７）和（Ｌｉ０．５Ｆｅ０．５）０．７ｙ＝Ｚｎ０．３ＣｏｙＦｅ２Ｏ４（ｙ＝０．０;０．０１;０．０２;０．０３）的Ｍｏｓｓｂａｕｅｒ谱,结果表明,离子代换使样品的Ｍｏｓｓｂａｕｅｒ谱变得复杂。所有谱线均包含一组强度很弱的顺磁双线亚谱。     

NaHSO4·SiO2催化制备生物柴油的研究

以NaHSO4·H2O、正硅酸乙酯和异丙醇为原料,经溶胶—凝胶法制备固体酸催化剂(NaHSO4·SiO2),进行了利用此催化剂催化油酸与甲醇的酯化反应制备生物柴油的实验,研究了催化剂焙烧温度、NaHSO4负载量、反应时间、催化剂质量分数、甲醇与油酸物质的量比等对油酸转化率的影响。实验结果表明:固体酸催化剂NaHSO4·SiO2在油酸与甲醇的酯化反应中具有很高的催化活性,当催化剂焙烧温度为200℃、NaHSO4负载量为15%、n(甲醇)∶n(油酸)=10∶1、催化剂质量占油酸质量的10%、反应时间5h时,酯化反应转化率可达95.19%。     

Fabrication and Magnetic Properties of Composite Ni_(0.5)Zn_(0.5)Fe_2O_4/Pb(Zr_(0.52)Ti_(0.48))O_3 Nanofibers by Electrospinning

One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4(NZFO)/ Pb(Zr0.52Ti0.48)O3(PZT) nanofibers with average diameters about 65 nm are prepared by electrospinning from poly(vinyl pyrrolidone) (PVP) and metal salts.The precursor composite NZFO/PZT/PVP nanofibers and the subsequent calcined NZFO/PZT nanofibers are investigated by Fourier transform infrared spectroscopy (FT- IR) ,X-ray diffraction (XRD),scanning electron microscopy (SEM).The magnetic properties for nanofibers are measured by vibrating sample magnetometer(VSM).The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases,which are constructed from about 37 nm NZFO and 17 nm PZT grains.The saturation magnetization of these NZFO/PZT nanofibers increases with increasing calcination temperature and contents of NZFO in the composite.     

复合磁性纳米粒子的合成和特性研究

通过在磁性纳米粒子表面修饰柠檬酸得到了分散性良好的水基磁流体,为了研究磁性纳米粒子在生物医药上的应用,通过Stober法合成了Fe3O4/SiO2复合粒子。透射电镜(TEM)和红外光谱仪(IR)研究表明,SiO2成功地包裹在Fe3O4粒子表面,且复合粒子的分散性好,粒径均匀。振动样品磁强计测试表明磁性复合粒子仍然具有较强磁性。