Influence of rare-earth metal doping on the catalytic performance of CuO-CeO_2 for the preferential oxidation of CO in excess hydrogen

Doping of different rare-earth metals （Pr, Nd, Y and La） had an evident influence on the catalytic performance of CuO-CeO2 for the preferential oxidation （PROX） of CO in excess hydrogen. As for Pr, the doping enhanced the catalytic activity of CuO-CeO2 for PROX. For example, the CO conversion over the above catalyst for PROX was higher than 99% at 120 °C. Especially, the doping of Pr widened the temperature window by 20 °C over CuO-CeO2 with 99% CO conversion. For Nd, Y, and La, the doping depressed the catalytic activity of CuO-CeO2 for PROX. However, the doping of transition metals markedly improved the selectivity of CuO-CeO2 for PROX.

Rare Earth Elements-Doped LiCoO_2 Cathode Material for Lithium-Ion Batteries

Some compounds of LiCo 1- x RE x O 2 (RE=rare earth elements and x =0.01～0.03) were prepared by doping rare earth elements to LiCoO 2 via solid state synthesis. The microstructure characteristics of the LiCo 1- x RE x O 2 were investigated by XRD. It was found that the lattice parameters c are increased and the lattice volumes are enlarged compared to that of LiCoO 2. Moreover, the performance of LiCo 1- x RE x O 2 as the cathode material in lithium ion battery is improved, especially LiCo 1- x Y x O 2 and LiCo 1- x La x O 2. The initial charge/discharge capacities of LiCo 0.99 Y 0.01 O 2 and LiCo 0.99 La 0.01 O 2 are 174/154 (mAh·g -1 ) and 159/149 (mAh·g -1 ) respectively, while those for LiCoO 2 working in the same way are only 139/131 (mAh·g -1 ).

Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

Some rare earth doping spinel LiMn_(2-x)RE_xO_4 (RE=La, Ce, Nd) cathode materials for lithium ion batteries were synthesized by the solid-state reaction method. The structure characteristics of these produced samples were investigated by XRD, SEM, and particle size distribution analysis. According to the microstructure and charge-discharge testing, the effect of doping rare earth on stabilizing the spinel structure was analyzed. Through a series of doping experiments, it is shown that when the doping content x within the range of 0.01～0.02 the cycle performance of the materials is greatly improved. The discharge capacity of the sample LiMn_(1.98)La_(0.02)O_4, LiMn_(1.98)Ce_(0.02)O_4 and LiMn_(1.98)Nd_(0.02)O_4 remain 119.1, 114.2 and 117.5 mAh·g^(-1) after 50 cycles.

稀土掺杂上转换纳米材料在金属离子检测领域中的应用

重点综述了基于稀土掺杂上转换纳米材料(REEs-UCNPs)构建荧光共振能量转移(FRET)体系或发光共振能量转移(LRET)体系来实现对金属离子定量分析检测的研究进展,并对REEs-UCNPs在生物医学、卫生分析和环境检测等领域应用的未来发展趋势进行了展望。

稀土纳米材料在脑肿瘤成像和治疗中的研究进展

脑肿瘤是最致命的疾病之一,由于缺乏有效的诊断和治疗手段导致其预后差、复发率高,患者5年生存率低。因此,许多研究人员致力于开发非侵入性高分辨率成像技术以获得脑肿瘤的解剖结构和信息,实现精准的早期诊断,并开发新型高效的治疗方式,以及诊断、治疗一体化的新范式。稀土纳米材料(Rare earth-based nanoparticles,RENPs)因其独有的优势被广泛应用于疾病诊断、药物输送、肿瘤治疗和生物成像等领域。RENPs具有独特的光学、磁学特性和高X射线吸收能力,可通过荧光成像、磁共振成像和计算机断层扫描成像对脑肿瘤进行高分辨率成像。RENPs的发射光可调谐,特别是其近红外第二生物学窗口(Second near-infrared,NIR-Ⅱ,1000~1700 nm)的发射具有较强的组织穿透性,低的背景荧光干扰,适合用于荧光成像探针及光响应性治疗的光刺激。重要的是,RENPs还具有优异的生物相容性以及表面易功能化等特点,可与抗体、肽和药物等生物大分子结合,以增强穿越血脑屏障(Blood-brain barrier,BBB)的能力,有利于靶向治疗和高对比度成像。因此,本综述重点介绍了RENPs在脑肿瘤成像和治疗领域的设计策略和应用,最后探讨了RENPs在肿瘤诊疗领域现有的挑战并对其未来的发展进行了展望。

A Study of Scandia Doped Tungsten Nano-Powders

Scandia and rhenium doped tungsten powders were prepared by solid-liquid doping combined with two-step reduction method. The particle size of doped tungsten and distribution of scandia and rhenium were studied by SEM, EDS, XRD and granularity analysis. Experimental results showed that scandia distributed evenly on the surface of tungsten particles. Addition of scandia and rhenium decreased the particle size of doped tungsten, and the more the content of scandia and rhenium, the smaller the doped tungsten particles. Tungsten powders doped with 3 % Sc2O3 and 3 % Re （mass fraction） had an average size of about 80 nm in diameter. The mechanism of the decrease in the tungsten particle size was discussed.

Transport Properties of Rare Earth Manganese Oxide La_(0.67)Ca_(0.33)Mn_(1-x)Fe_xO_3

The transport properties were studied for rare earth manganese oxide La_(0.67)Ca_(0.33)Mn_(1-x)Fe_xO_3 (x=0～0.3) systems. It is found that with increasing Fe^(3+)-doping content x, the resistance increases and the insulator-metal transition temperature (T_(IM)) shifts to lower temperature. If the doping content is small, the transport properties manifest metallic characteristics in the temperature range of T<T_(IM), while they will obey a thermal activation model in the temperature range of T>T_(IM). Such a behavior may be attributed to the Fe^(3+)-doping and possible Mn ions scattering to electrons. The Fe^(3+) doping may lead to the formation of Fe^(3+)-O^(2-)-Mn^(4+) channels, which could terminate the double exchange Mn^(3+)-O^(2-)-Mn^(4+) channels. The antiferromagnetic clusters of Fe ions may induce the Mn ions to scetter to the electrons.

Spontaneous Magnetic Transitions and Corresponding Magnetoelastic Properties of Intermetallic Compounds RMn_2Ge_2(R=Gd, Tb and Dy)

The spontaneous magnetic transitions and corresponding magnetoelastic properties of intermetallic compounds RMn2Ge2（R=Gd, Tb and Dy） were investigated by using the X-ray diffraction method and magnetic measurement. The results showed that the compounds experience two magnetic transitions, namely the second-order paramagnetic to antiferromagnetic transition at temperature TN（TN=368, 423 and 443 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） and the first-order antiferromagnetic-ferrimagnetic transition at temperature Tt（Tt=96, 80 and 40 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） as the temperature decreases. The temperature dependence of the lattice constant a（T） displays a negative magnetoelastic anomaly at the second-order transition point TN and, at the first-order transition Tt, a increases abruptly for Gd Mn2 Ge2 and Tb Mn2 Ge2, Da/a about 10^（-3）. Nevertheless, the lattice constant c almost does not change at these transition points indicating that such magnetoelastic anomalies are mainly contributed by the Mn-sublattice. The transitions of the magnetoelastic properties are also evidenced on the temperature dependence of magnetic susceptibility χ. The first-order transition behavior at Tt is explained by the Kittel mode of exchange inversion.

Removal of organic pollutants by lanthanide-doped MIL-53(Fe) metal-organic frameworks:Effect of dopant type in magnetite precursor

A series of undoped and lanthanide doped MIL-53(Fe)/Ln-Fe_(3)O_(4)(Ln=La,Nd,or Gd) metal-organic frameworks(MOFs) were prepared by the solvothermal method.All prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),Brunauer-Emmett-Teller(BET) measurements,scanning electron microscopy(SEM),and thermal analysis.XRD and FT-IR results ascertain the successful MOF formation for all prepared samples.MIL-53(Fe)/La-Fe_(3)O_(4) has the smallest particle size of 8.6 nm,the largest BET surface area of 54.2 m^(2)/g,and the highest porosity.Undoped and different lanthanide doped MIL-53(Fe) we re employed as sorbents for the removal of methylene blue(MB)dye from aqueous solutions to examine the doping benefit and the effect of the dopant size on the sorption performance.Doping causes MOFs to act as pH-independent sorbents,which make it applicable at any condition.Adsorption follows pseudo-second-order kinetic model,and doped sorbents attain equilibrium faster.Langmuir isotherms are followed,except for MIL-53(Fe)/La-Fe_(3)O_(4).The adsorption capacity increases with increasing the dopant ion size,100.5 mg/g for La-doped MOF,which is about four times higher than that of undoped MOF.The adsorption mechanism involves chemical interactions between Lewis acid in magnetite MIL-53(Fe) series and Lewis base in MB.

Applications of Rare Earth Promoted Transition Metal Sulfides in Electrocatalysis

With the rapid consumption of fossil fuels and the resulting environmental problems,researchers are working to find sustainable alternative energy and energy storage and conversion methods.Transition metal sulfur compounds have attracted extensive attention due to their excellent electrical conductivity,low cost,adjustable components and good electrocatalytic performance.As an alternative to noble metal catalysts,they have emerged as a promising electrocatalyst.However,their low catalytic activity and poor stability limit their large-scale practical applications.Rare earth elements,known as industrial vitamins,are widely used in various fields due to their special redox properties,oxygen affinity and electronic structure.Therefore,the construction of rare earth promoted transition metal sulfides is of far-reaching significance for the development of catalysts.Here,we review the applications of various rare earth promoted transition metal sulfides in energy storage and conversion in recent years,which focuses on three ways in rare earth promoted transition metal sulfide,including doping,interfacial modification engineering and structural facilitation.As well,these materials are used in electrochemical reactions such as OER,HER,ORR,CO_(2)RR,and so on,in order to explore the important role of rare earth in the field of electrocatalysis,the future challenges and opportunities.

燃烧法制备亚微米Co^(3+)掺杂LaBO_(3)粉体及表征

以La(NO_(3))_(3)·6H_(2)O、Co(NO_(3))_(3)·6H_(2)O、H_(3)BO_(3)和C_(2)H_(5)NO_(2)为原料,采用燃烧法合成Co^(3+)掺杂LaBO_(3)粉体,其中原料摩尔比为[La(NO_(3))_(3)·6H_(2)O+Co(NO_(3))_(3)·6H_(2)O]:H_(3)BO_(3):C_(2)H_(5)NO_(2)=3:3:5,研究了目标产物La((1-x))Co_(x)BO_(3)(x=0.01~0.04)在750~950℃的合成反应过程及产物结晶形态,分析了合成条件对产物晶体形态的影响,得到了最佳的原料配比、反应温度、反应时间和掺杂量。结果表明,燃烧合成法可用于制备Co^(3+)掺杂LaBO_(3)粉体,且实验条件简单,煅烧温度较低,产率高,易于工业化。最佳反应条件为900℃、4 h,改性剂钴的掺杂量为x=0.03,产物为La_(0.97)Co_(0.03)BO_(3)粉体。在该反应条件下,产物颗粒大小均匀,为直径115~185 nm、长度400~600 nm的短棒状粉体。Co^(3+)掺杂LaBO_(3)粉体产物在330~440 nm处出现一个较宽的荧光激发带,说明具有较为均匀粒径和晶体形貌的Co^(3+)掺杂LaBO_(3)粉体可以作为制备发光粉体的基质材料。

离子掺杂羟基磷灰石的抗菌改性研究进展

骨修复材料植入术所造成的局部感染是手术并发症中之一,会导致手术失败并且增加患者治疗或二次手术的痛苦和费用。羟基磷灰石(Hydroxyapatite)材料具有与生物硬组织相似的结构与化学组成,具有优异的生物活性,备受国内外研究者们的关注。羟基磷灰石本身无抗菌特性,然而离子的掺杂赋予了羟基磷灰石出色的抗菌特性以及其他各类特性。当前研究的热点主要是常见金属离子元素掺杂羟基磷灰石的特性,近年来,一些类金属、重金属和部分镧系稀土元素掺杂的羟基磷灰石也开始获得研究。本文综述了一些常见的金属离子,镧系稀土金属离子,非金属离子还有其他离子单一掺杂和多种离子共掺杂羟基磷灰石的抗菌性能的研究进展,最后对存在的问题及未来的发展做了总结及展望。

First-principles prediction of the magnetism of 4f rare-earth-metal-doped wurtzite zinc oxide

Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied DMSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.

稀土Eu掺杂对金属氧化物涂层阳极电催化性能的影响

通过掺杂实验发现稀土Eu的添加有利于提高金属氧化物涂层阳极的电催化性能 ,X射线衍射的结果表明稀土缺氧氧化物Eu3O4 的形成是电催化性能提高的主要原因。Eu掺杂成型工艺表明较高的热分解温度有利于晶粒的细化 ,使电极具有好的电催化性能 ,最佳温度值在 5 0 0℃左右 ;Eu的添加量在主溶液离子浓度与稀土离子浓度之比为 10∶2时最佳。EDX扫描分析的结果表明用化学溶液涂覆法制备的涂层成分分布均匀。

溶胶凝胶法制备TiO_2纳米颗粒及其光催化性能

考察了通过溶胶凝胶法进行过渡金属(Fe3+、Zn2+、Co2+、Ni2+、Cr3+和Sn4+)和稀土元素(La3+、Pr3+、Nd3+、Ce4+、Sm3+、Tb3+、Eu3+、Gd3+、Y3+和Dy3+)掺杂的TiO2纳米颗粒的光催化活性,以及通过超声波处理反应过程中的溶胶所制备得到的TiO2纳米颗粒的光催化活性。结果表明0.5%Sn4+、0.5%La3+、0.5%Y3+和0.5%Eu3+(质量分数)掺杂的TiO2纳米颗粒在降解甲基橙溶液的反应中,其光催化活性提高2%～7%;其它的掺杂则使TiO2纳米颗粒的光催化活性降低0.5%～25%;在TiO2纳米颗粒的制备过程中,对溶胶进行超声辐照可使其光催化活性提高15%以上,这是提高TiO2纳米颗粒光催化活性的一条新途径。

稀土磷酸盐纳米发光材料的研究进展

综述了稀土磷酸盐纳米发光材料的最新研究进展。总结了稀土磷酸盐纳米发光材料的制备方法,重点介绍了水热合成法、超声合成法及微波合成法等在制备稀土磷酸盐纳米发光材料中的应用和发展;从微观结构的角度对稀土磷酸盐纳米发光材料的发光机理进行了详细的阐述,着重讨论了稀土离子掺杂、壳核结构及形貌和晶型结构对稀土磷酸盐纳米材料发光特性的影响;为更加深入探索和研究稀土纳米发光材料提供了有用的参考信息。

稀土离子(Ce^(3+),Tb^(3+),Pr^(3+))掺杂重金属锗酸盐玻璃的光谱透过及抗辐射性能

从新型抗辐射闪烁体材料的应用背景出发 ,对某些稀土离子掺杂重金属锗酸盐玻璃进行了紫外与可见光谱区的透过性能及抗辐射性能的表征 ,重点讨论玻璃基质组成与短波截止波长之间的关系以及一些元素对玻璃抗辐射性能的影响。玻璃基质组成涉及GeO2 ,Gd2 O3,BaO ,SnO ,La2 O3,掺杂的稀土元素包括Ce3+ ,Tb3+ ,Pr3+ 。实验结果表明 :这些重金属锗酸盐玻璃的紫外截止波长适中 ( 35 0nm ) ,适于用作掺杂稀土离子的基质材料。Sn2 + 和Ce3+ 使玻璃的紫外截止波长明显红移 ,其原因与特殊的紫外吸收机理有关。在所加入的元素中 ,Sn2 +和稀土离子Ce3+ ,Tb3+ ,Pr3+ 均对玻璃的抗辐射性能有增强作用 ,其中以Ce3+ 抗辐射效应最为明显 。

稀土及过渡金属掺杂TiO_2的制备及光催化性能研究

选用六水合硝酸镧(La(NO_3)_3·6H_2O)及六水合硝酸钴(Co(NO_3)_2·6H_2O)为掺杂剂,以钛酸四丁酯(TBOT)为原料,采用水热法制备了稀土La及过渡金属Co共掺杂的二氧化钛(TiO_2)复合光催化剂,并通过XRD、SEM、EDS、FT-IR表征手段对样品进行了分析。以甲基橙为模型污染物,研究La及Co共掺杂量对复合光催化剂活性的影响。结果表明:通过水热法制备的催化剂为球型结构的金红石相,掺杂La和Co并未改变TiO_2的晶体结构;(La/Co)/TiO_2复合材料对甲基橙的降解能力相比纯TiO_2有显著提高,当La及Co的共掺杂量为1%(mol,摩尔含量)时,降解效果最好,最高降解率可达到98.2%。

CeO_2基体掺杂材料及其在SOFC中的应用

氧化铈(Ce O2)基体掺杂材料作为电解质基体材料而被广泛应用于中低温固体氧化物燃料电池(SOFC)中。不同的金属元素掺杂Ce O2会表现出不同的优良性质。就碱土金属掺杂、稀土金属掺杂、碱金属掺杂和其他过渡金属掺杂Ce O2材料表现出的共性和特性,及其对固体氧化物燃料电池的性能影响进行了详细的介绍。

Nd_2O_3掺杂(BaSr)TiO_3对陶瓷结构和性能的影响

采用常规固相反应法,以Ba0.6Sr0.4TiO3+10%MgO(BSTO)体系为基体成分,研究了Nd2O3掺杂对其显微组织结构和介电性能的影响规律,结果表明掺杂Nd2O3后,抑制了BSTO晶粒的生长;随着Nd2O3掺杂量的增加,陶瓷的晶粒尺寸变小,密度增大,材料的居里温度向负温度方向移动,并且展宽了介电峰,使材料的温度稳定性提高,此外,随着Nd2O3掺杂量的增加,材料的可调性减小,介电常数减小。