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51.
《印度化学会志》2023,100(7):101026
This work investigated the structural, morphological, elemental, optical, and electrochemical characteristics of nickel phosphate nanoparticles co-precipitated at varying molar concentrations. Structural results gave monoclinic crystalline phase with nanorod morphology. EDX plots confirmed deposition of constituent element: nickel, phosphorus and oxygen. The films exhibited good absorbance feature with optical energy band gap values ranging from 1.58 eV to 2.2 eV. Good cyclic reversibility as obtained using 0.1 M of sodium hydroxide as electrolyte. The specific capacitance values of the electrodes ranged from 624.38 F/g to 1017.2 F/g at a scan rate of 1 mV/s. The Ni3(PO4)2 electrode prepared at 0.3 M recorded maximum energy and power densities of 239.49 Wh/kg and 2.52 W/kg respectively. The synthesized samples find potential application in optical and electrochemical devices. 相似文献
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在以共沉淀法制备的磁性纳米Fe3O4粒子(Magnetic nanoparticles, MNP)表面进行了化学修饰, 制备了一种新型富含羧基功能团的核壳磁性纳米吸附剂(Carboxylic functionalized Fe3O4 magnetic nanoparticles, CMNP). 利用透射电子显微镜(TEM)、 X射线衍射仪(XRD)、 X射线能量色散谱(EDS)、 振动样品磁强计(VSM)、 傅里叶变换红外光谱(FIIR)和热重分析仪(TGA)对CMNP的形貌、 结构、 化学组成和磁性能进行了表征, 并考察了吸附剂对Cu2+的吸附性能, 研究了溶液pH值、 吸附时间和Cu2+初始浓度对吸附性能的影响. 结果表明, 羧基化核壳磁性纳米Fe3O4颗粒的平均粒径为15 nm, 具有良好的超顺磁性, 饱和磁化强度为41.84 A·m2/kg, 在10 min中内可达到吸附平衡, 在pH=7.0时吸附量最高, 吸附等温数据符合Langmuir模型, 饱和吸附量qm= 43.48 mg/g. 相似文献
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Irshad Ali M.U. Islam M. Ishaque Hasan M. Khan Muhammad Naeem Ashiq M.U. Rana 《Journal of magnetism and magnetic materials》2012
CoHoxFe2−xO4 ferrites (x=0.00–0.1) were prepared by the co-precipitation technique and the effect of holmium substitution on the magnetic properties was investigated. X-ray diffraction reveals that the substituted samples show a second phase of HoFeO3 along with the spinel phase. The magnetic properties such as the saturation magnetization (Ms), coercivity (Hc) and remanence (Mr) are obtained from the hysteresis loops. It is observed that the Ms decreases while Hc increases with Ho3+ substitution. The decrease of saturation magnetization is attributed to the weakening of exchange interactions. The coercivity increases with increase of the Ho3+ concentration, which is attributed to the presence of an ultra-thin layer at the grain boundaries that impedes the domain wall motion. Low field AC susceptibility was also measured over the temperature range 300–600 K at the frequency of 200 Hz. It decreases with the increase of temperature following the Curie–Weiss law up to the Curie temperature. Above the Curie temperature it shows paramagnetic behavior. The increase in coercivity suggests that the material can be used for applications in perpendicular recording media. 相似文献
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Yue Zhang Zhi Yang Yong Liu Rui Xiong Jing Shi GaoLin Yan 《Journal of magnetism and magnetic materials》2010,322(21):3470-3475
Cobalt ferrite nano-particles were prepared using the co-precipitation method followed by annealing treatment. The formation of nano-particles with different composition, microstructure and sizes were confirmed by X-ray diffraction, Raman, thermogravimetric-differential thermal analysis and transmission electron microscope. The magnetic hysteresis loops measured at room temperature revealed smaller effective magnetic anisotropy constant, coercivity and remanence ratio for the samples prepared by adding the NaOH solutions into the mixed solutions of Co2+ and Fe3+ ions due to the formation of Co3+ ions. A small saturation magnetization and an enhanced coercivity were observed for the nano-particles prepared by adding the mixed solutions of Co2+ and Fe3+ ions into the NaOH solutions, which was related to the formation of outer layers with poor crystallization on the surfaces of the cobalt ferrite nano-crystals. Furthermore, the existence of these outer layers induced the oxidation of Co2+ ions in cobalt ferrite nano-crystals at 200 and 300 °C, and led to a large change on the composition and magnetic properties. 相似文献
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通过在碱液中共沉淀Mn2+、Ni2+和Fe2+后制备了棒状的前躯体,前躯体于不同温度煅烧后制得了MnxNi0:5-xZn0:5Fe2O4棒状体. 利用X射线衍射仪和透射电镜对棒状体的物相、形貌及粒径进行了表征,并利用振动样品磁强计对磁性能进行研究. 结果表明长径比大于15的棒状,随着x值的增加,MnxNi0:5-xZn0:5Fe2O4样品的直径增加,长度下降,长径比变小,当x=0.5时其直径在50 nm左右而长径比减小到7~8. 随着x值的增加,样品的矫顽力先增加后减少,x值达到0.4时样品的矫顽力再次增加,当煅烧温度为600 oC,x=0.5时样品的矫顽力最大为134.3 Oe. 饱和磁化强度随着x值的增加先增加后减少,当煅烧温度为800 oC和x=0.2时达到最大为68.5 Oe. 相似文献
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Y2O3:Eu3+, Tb3+ phosphors with white emission are prepared with different doping concentration of Eu3+ and Tb3+ ions and synthesizing temperatures from 750 to 950 °C by the co-precipitation method. The resulted phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results of XRD indicate that the crystallinity of the synthesized samples increases with enhancing the firing temperature. The photoluminescence spectra indicate the Eu3+ and Tb3+ co-doped Y2O3 phosphors show five main emission peaks: three at 590, 611 and 629 nm originate from Eu3+ and two at 481 and 541 nm originate from Tb3+, under excitation of 250-320 nm irradition. The white light luminescence color could be changed by varying the excitation wavelength. Different concentrations of Eu3+ and Tb3+ ions were induced into the Y2O3 lattice and the energy transfer from Tb3+→Eu3+ ions in these phosphors was found. The Commission International de l’Eclairage (CIE) chromaticity shows that the Y2O3:Eu3+, Tb3+ phosphors can obtain an intense white emission. 相似文献
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Javed Ahmad Muhammad Qadeer AwanMuhammad Ehsan Mazhar Muhammad Naeem Ashiq 《Physica B: Condensed Matter》2011,406(2):254-258
Cobalt substituted nanosized magnesium aluminates having a nominal composition MgAl2−xCoxO4 where x = 0.0, 0.5, 1.0, 1.5, 2.0 were synthesized by the chemical co-precipitation method. Aluminium (Al3+) ions were completely and successfully substituted by Co2+ ions, which yielded an electron rich terminal compound MgCo2O4. All the samples were characterized by means of X-ray diffraction (XRD), thermogravimetry and differential thermal analysis (TG/DTA) and dc electrical resistivity measurements. The investigated samples were found to be spinel single phase cubic close packed crystalline materials as demonstrated by XRD data. Using the Debye Scherer formula, the calculated crystallite size was found Co2+ concentration dependent and varied between 7 and 19 nm. The lattice constant, X-ray density and bulk density were found to increase while percentage porosity decreases on increasing the Co2+ concentration. The dc electrical resistivity was found to decrease as a function of temperature as expected for a typical semiconductor. The doped Co2+ ions are believed to form small polarons and hopping of these small polarons between the adjacent sites seems to be partially responsible for conduction in the system. The activation energy of hopping of small polarons was also calculated. 相似文献
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通过化学共沉淀法制备了适合近紫外激发的SrZn1-x(WO4)2∶xTb3+∶yCe3+系列绿色荧光粉。利用X射线衍射(XRD)分析了不同掺杂比例对样品物相的影响。采用荧光光谱(PL)对样品的激发光谱和发射光谱进行了表征。分别讨论了稀土Tb3+单掺及Ce3+和Tb3+共掺对样品发光性能的影响。XRD分析表明:样品的主衍射峰与标准卡片(JCPDS 08-0490和JCPDS 15-0774)的衍射峰基本一致,说明单掺和共掺稀土离子均未改变基质晶格结构。在样品的激发光谱中,223nm为主激发峰,属于Tb3+的7F—7 D自旋允许跃迁。在223nm的紫外光激发下,样品发射光谱主发射峰位置在543nm,归属于Tb3+的5 D4→7 F5跃迁。当Ce3+和Tb3+共掺时,峰型和位置变化不大,Ce3+和Tb3+掺杂摩尔分数比为0.02∶0.06时,发光强度得到很大提高,说明Ce3+和Tb3+之间存在着能量传递。 相似文献