稀土掺杂硼酸盐Bi2ZnB2O7: xDy3+光催化剂的合成及其催化机理

采用高温固相反应法制备了一系列镝离子掺杂Bi₂ZnB₂O₇（BZBO）光催化剂。通过XRD、TEM和HRTEM等手段对BZBO: xDy³⁺材料的结构及形貌等进行了表征,通过RhB溶液在紫外灯下的光降解实验研究了不同浓度镝离子掺杂对BZBO光催化性能的影响。RhB光降解实验结果表明,当Dy³⁺在BZBO中的掺杂量为4%时,BZBO: 4%Dy³⁺具有最好的光降解活性,其光降解活性为纯BZBO的1.56倍。通过光吸收性能分析可知,Dy³⁺的引入增强了BZBO的紫外吸收强度,并稍降低了其禁带宽度。光吸收性能、光致发光光谱、光电流和EIS实验结果表明,BZBO: 4%Dy³⁺的光催化活性增强的主要原因是BZBO中掺杂的镝不仅提高了BZBO光催化剂的光吸收能力,更促进了光生电子-空穴对的分离和转移。因此,在稀土元素和极化电场的作用下,BZBO: 4%Dy³⁺的光催化活性要高于其他所制备的样品。     

Synthesis of Dy2O3 nanoparticles via hydroxide precipitation： effect of calcination temperature

This work described the preparation of dysprosium oxide, Dy2O3, nanoparticles using the homogeneous precipitation method. Dy3+ ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300–700 °C in static air. The calcination temperature of the Dy-precursor was chosen based on its decomposition as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The obtained results revealed that Dy2O3 with crystallites size of 11–21 nm was formed at 500 °C. Such value increased to 25–37 nm for the sample calcined at 700 °C.     

Palladized dysprosium fluoride nanorods as a new performance catalyst in direct methanol fuel cell

Fuel cells are a new type of batteries that produce electricity from a continuous source of alcohols as long as fuel is inserted. In this study, decorated palladium nanoparticles (PdNPs) on dysprosium fluoride (DyF₃) nanorods (DyFNRs)‐multiwalled carbon nanotubes (MWCNTs) were used for electrooxidation of methanol. DyFNRs were synthesized by the hydrothermal method, and the proposed multifunctional catalyst (DyFNRs/MWCNT‐PdNPs) was identified by several methods such as X‐ray diffraction, elemental mapping images, field emission scanning electron microscopy, energy dispersive analysis of X‐rays, and transmission electron microscopy which demonstrated a uniform distribution and high dispersion of the PdNPs on the supports. The electrocatalytic activity toward methanol electrooxidation on glassy carbon electrode (GCE) with DyFNRs/MWCNT‐PdNPs (DyFNRs/MWCNT‐PdNPs/GCE) was investigated by cyclic voltammetry (CV) and chronoamperometry (CA). Experimental results showed a high improvement in oxidation potential and peak current of methanol electrooxidation by DyFNRs/MWCNT‐PdNPs in comparison to DyFNRs and PdNPs. The values of the catalytic rate constant (k) and physical dimension (D_s) for methanol oxidation on the DyFNRs/MWCNT‐PdNPs/GCE catalyst were calculated 0.008 s^?1 and 1.43, respectively. Moreover, the order of reaction was determined to be 0.43 and 0.13 for CH₃OH and NaOH, repectively. Finally, the synthesized catalyst was evaluated in direct methanol fuel cell (DMFC). The single DMFC with proposed anodic catalyst, DyFNRs/MWCNT‐PdNPs, indicated a power density of 4.4 mW·cm^?2 at a current density of 18 mA·cm^?2 in alcohol (1 M) and NaOH (1 M).     

表面修饰对镝铁氧体纳米磁粒子的合成及其磁性能的影响

利用湿化学法制备镝铁氧体纳米磁粒子时,用适量的阴离子表面活性剂进行表面修饰,能够有效地控制磁粒子的粒径,同时避免干燥时产生硬团聚.文章介绍了用月桂酸、月桂酸钠、正十二烷基硫酸钠对磁粒子进行表面修饰的研究结果,探讨了三者及其用量对磁粒子的形成及磁性能的影响.借助X射线衍射仪(XRD)、透射电镜(TEM)、振动样品磁强计(...     

稀土离子掺杂锆酸钙纳米晶的制备及发光性质

采用溶胶–凝胶法在700℃和较短的煅烧时间下制备了钙钛矿结构的CaZrO3和不同浓度的Eu3＋、Dy3＋掺杂的CaZrO3纳米晶粉末,对合成产物的发光性质进行研究。结果表明：Eu3＋掺杂的CaZrO3样品在590～630 nm之间有强的橙红光发射,在Eu3＋掺量为5.0%（摩尔分数,下同）时发光强度达到最高值。Dy3＋...     

发射光谱法测定氧化镝中的14个稀土元素

用发射光谱法测定氧化镝中的 14个稀土元素 ,其中 Ce,Pr,Tb的检出限为0 .0 3%(质量分数 ,下同 ) ;L a,Nd,Sm,Eu,Gd,Ho,Tm,L u的为 0 .0 1%;Er,Yb,Y的为0 .0 0 5%.该方法的相对标准偏差为 7.4 2 %～ 2 1.2 2 %( n=2 5) .     

镝的光度分析进展

对近10a来的用荧光法和导数光谱法测定镝的研究及应用进行了综合报道。参考文献30篇。     

Thermokinetics of Liquid-Liquid Reaction of Dy（NO3 ）3 with Histidine

The thermokinetics of liquid-liquid reaction of dysprosium nitrate with histidine were studied using a microcalorimeter. On the basis of experimental and calculated results, threethermodynamic parameters (the activation enthalpy, the activation entropy and the activation free enegy),the rate constant, three kinetic parameters (the activation energy, the pre-exponential constant and the reaction order) wereobtained. On the basis of thermodynamics and kinetics, the for marion reaction of the complex was discussed.     

High-energy NdFeB magnets and their applications

In sintered NdFeB magnets, additive elements for increasing coercivity decrease residual magnetization. Also, fine magnetic powder oxidization prevents identification of the stoichiometry composition (Nd ₂Fei₁₄B).To improve the magnetic properties of a sintered NdFeB magnet, the authors have developed a method involving two alloys. Magnetic Nd ₂Fei₁₄Balloy and a rare- earth- rich alloy (including richer dysprosium content) are melted individually and mixed together after coarse pulverization. After the sintering process, dysprosium in the sintered body is enriched in each grain region near the grain boundary. The two- alloy method minimizes the liquid phase necessary to keep the coercive force at a useful level, and thus results in compositions closer to stoichiometry. The energy product of magnets having an inhomogeneous dysprosium distribution is typically 360 kj - m ^{- 3} (45 MG.Oe) at production level. The corrosion characteristics of cobalt- substituted NdFeB magnets also were investigated. These magnets are now used in voice coil motors for hard disk drives and contribute to shortening access time and hard- drive downsizing.     

络合交换乳状液膜分离稀土镝和铥

本文从理论上探讨了络合交换液膜分离稀土的机理，并将其应用于稀土元素的相互分离。实验结果表明，在适当的条件下，采用络合交换液膜分离性质相似的稀土元素镝和铥，可以显著地改善稀土分离效果，达到有效分离稀土镝和铥的目的，实验结果和理论预测相符合。