Formation of substitutional metallofullerenes by laser ablation of externally doped fullerenes C60M x (M=Sm, Pt, Ni and Rh)

Photofragmentation study of metal fullerides C₆₀M _x (M = Sm, Pt, Ni and Rh) by excimer laser ablation-TOF mass spectrometry shows that metallofullerenes C_2n M and C_2n+1M formed in both the positive and negative ionic modes. The isotopic distributions of the metallofullerenes C_2n M and C_2n+1M are consistent with the calculated spectra based on the natural abundance of isotopes of C and M, confirming the formation of metallofullerenes. The metal atom is supposed to be incorporated into the network of the fullerene cage to replace one carbon atom of the cage forming substitutional metallofullerene. Odd-numbered high carbon clusters are observed in our laser ablation study of all the metal fullerides in the negative ion channel. Evolution of mass spectrum with irradiation laser shots shows that the formation of the substitutionally doped fullerenes is closely related to the production of metal carbide (MC). The structures, as well as formation mechanism, of metallofullerenes C_2n+1M and C_2n M with even and odd numbers of total atoms respectively are discussed based on the structural optimization of the odd-numbered high carbon clusters.     

In situ U-Pb dating of xenotime by laser ablation （LA）-ICP-MS

Xenotime is an ideal mineral for U-Th-Pb isotopic dating because of its relatively high U and Th contents, but typically low concentration of common Pb. These characteristics, and the fact that it is widespread throughout various types of rocks, suggest that the U-Th-Pb dating of xenotime has broad applications. Studies of U-Pb dating on xenotime by ion microprobe (such as SHRIMP) have increased in recent years, whereas studies by laser ablation (LA)-ICP-MS are still rare. In this study, we developed a technique for U-Pb dating of xenotime using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. To evaluate the reliability of our method, a xenotime standard, BS-1, was analyzed and calibrated against another xenotime standard, MG-1. The weighted mean 206 Pb/ 238 U ages of 510.1 ± 5.2 Ma (2 n = 21), 509.8 ± 4.3 Ma (2 n = 21) and 510.0 ± 4.6 Ma (2 n = 21) were obtained using beam diameters of 16, 24 and 32 m, respectively. These ages are identical to those determined by ID-TIMS method (weighted mean 206 Pb/ 238 U age of 508.8 ± 1.4 Ma), which supports the reliability of our LA-ICP-MS method. We also analyzed xenotimes in leucogranites from South Tibet and granites from Xihuashan in southern China, and obtained accurate and precise ages. Nevertheless, we observed systematic differences in Pb/U fractionation among xenotime, monazite and zircon. The matrix-effect resulted in either under-correction or over-correction of fractionation, and thus led to inaccurate ages. Thus, a matrix-matched material is required for U-Pb dating of xenotime by LA-ICP-MS.     

Theoretical study on photophysical property of C60M（CO）5 （M=Cr,Mo and W）

Configurations of three η2 models of transition-metal [60]fullerene derivatives C60M（CO）5（M=Cr, Mo and W） have been optimized at B3LYP/LanL2DZ level. On the basis of the optimized geometrical structures, their electronic spectra and the frequency dependence of third-order nonlinear optical polarizabilities γ in different optical processes of third-harmonic generation （THG）, electric-field-induced second-harmonic generation （EFISHG） and degenerate four-wave mixing （DFWM） are calculated by using TDB3LYP model based on LanL2DZ level coupled with the SOS （sum-over-state） method. The obtained results show that their electronic spectra have a red shift compared with that of [60]fullerene and different transition-metal functional groups added to C60 cage may result in different spectrum properties. For the three studied species, （η^2-C60）Mo（CO）5 has the largest third-order nonlinear optical polarizability.     

Azo dye degradation behavior of AlFeMnTiM (M=Cr,Co, Ni) high-entropy alloys

Because of the potential carcinogenic effects and difficult degradation of azo dyes, their degradation has been a longstanding problem. The degradation of azo dye Direct Blue 6(DB6) using ball-milled(BM) high-entropy alloy(HEA) powders was characterized in this work. Newly designed AlFeMnTiM(M = Cr, Co, Ni) HEAs synthesized by mechanical alloying(MA) showed excellent performance in the degradation of azo dye DB6. The degradation efficiency of AlFeMnTiCr is approximately 19 times greater than that of the widely used commercial Fe–Si–B amorphous alloy ribbons and more than 100 times greater than that of the widely used commercial zero-valent iron(ZVI) powders. The galvanic-cell effect and the unique crystal structure are responsible for the good degradation performance of the BM HEAs. This study indicates that BM HEAs are attractive, valuable, and promising environmental catalysts for wastewater contaminated by azo dyes.     

分子导体(PyH)[M(dmit)2]2(M=Pd,Ni)的晶体结构与能带结构

在配合物型分子导体(PyH)[Pd(dmit)2]2和(PyH)[Ni(dmit)2]2中,阴离子导电组元[M(dmit)2]^0．5-(M=Pd,Ni)的面对面堆积和肩并肩排列形成二维层状结构．采用推广休克尔紧束缚方法计算了二维导电层中相邻两阴离子的HOMO轨道的重叠积分,并进行了二维能带计算．计算结果表明它们是窄能隙半导体。与晶样的变温电导测试的结果一致.     

Hydrogen storage performances of the as-milled REMg11Ni (RE = Sm, Y) alloys catalyzed by CeO2

The addition of catalysts and rare earth elements is considered to be very effective methods to enhance the hydrogenation/dehydrogenation properties of Mg and Mg-based hydrides. In this paper, the REMg11 Ni+ 5 wt%CeO_2(RE = Sm, Y)(named REMg11 Ni-5 CeO_2(RE = Sm, Y)) alloys were fabricated through ball milling. The phase composition and structure of the as-milled alloys were investigated in detail. The isothermal hydrogen storage thermodynamics and kinetics of the as-milled alloys were measured by using an automatically Sievert apparatus. Non-isothermal dehydrogenation performance of the alloys was investigated by thermogravimetry(TG) and differential scanning calorimetry(DSC) at different heating rates. The results revealed that all the asmilled alloys were the nanocrystalline and amorphous structure. The RE = Y alloy had a faster hydriding rate and a lower onset hydrogen desorption temperature than the RE = Sm alloy. The superior property of the RE= Y alloy depended on the decrease of the dehydrogenation activation energy. By means of the measurement of Pressure-Composition-Isotherm(P-C-T) curves, the thermodynamic parameters of the REMg11 Ni-5 CeO_2(RE =Sm, Y) alloys were calculated, and the dehydrogenation enthalpy change was 74.86 k J/mol for the RE = Sm alloy and 73.75 k J/mol for the RE = Y alloy, respectively.     

金属串配合物[CoMCo(dpa)4(NCS)2](M=Co,Ni,Pd,Pt)结构和自旋过滤性质研究

应用密度泛函理论B3LYP方法对金属串配合物[CoMCo(dpa)4(NCS)2](1:M=Co, 2:M=Ni, 3:M=Pd, 4:M=Pt; dpa=dipyridylamide)的成键性质和自旋过滤效应进行了研究,结果表明：配合物1的基态为二重态,Co36+金属链形成三中心三电子键(2nb1*0);而配合物2~4的基态均为反铁磁耦合单重态(AF态),对应的最低能量高自旋态(HS态)分别为三重态、七重态和七重态,单电子分布在两端Co原子上,[CoMCo]6+链具有三中心四电子键(2nb1*1)。由分子轨道能级图和PDOS图分析得到配合物1~4均具有自旋过滤效应,电子传输通道主要为-自旋nb轨道,与费米能级的距离大小为1234。电场作用下,1~4的高电势端Co2―N4键增长而低电势端Co3―N7键缩短,Co―M平均键长略为缩短,Co―M键增强;电场作用下金属原子的自旋密度和电荷密度变化很小,电磁性质稳定;电场作用下nb轨道分布仍保持沿金属轴方向离域,LUMO-HOMO能隙减小,有利于电子输运。     

Theoretical study on photophysical property of C_(60)M(CO)_5 (M=Cr,Mo and W)

Configurations of three η2 models of transition-metal 60 fullerene derivatives C60M(CO)5(M=Cr,Mo and W) have been optimized at B3LYP/LanL2DZ level.On the basis of the optimized geometrical structures,their electronic spectra and the frequency dependence of third-order nonlinear optical polarizabilities γ in different optical processes of third-harmonic generation(THG),electric-field-induced sec-ond-harmonic generation(EFISHG) and degenerate four-wave mixing(DFWM) are calculated by using TDB3LYP model based on LanL2DZ level coupled with the SOS(sum-over-state) method.The obtained results show that their electronic spectra have a red shift compared with that of 60 fullerene and dif-ferent transition-metal functional groups added to C60 cage may result in different spectrum properties.For the three studied species,(η2-C60)Mo(CO)5 has the largest third-order nonlinear optical polarizability.     

MX(M=Fe,Ru,Co和Rh, X= Si和Ge) 合金化合物的热力学性质和硬度的第一性原理计算

基于第一性原理,利用赝势平面波法分析MX型合金化合物的结构性质、弹性性质和力学稳定性。计算得到的MSi/Ge的结构参数和形成焓与实验结果以及其他理论计算结果相吻合,结果表明MSi/Ge具有热力学稳定性且易于合成。计算得到了MX型合金化合物的弹性常数、体积模量、剪切模量、杨氏模量、弹性各向同性指标以及泊松比。基于弹性常数,得到了CoSi/Ge和RhSi/Ge的德拜温度-压强曲线。基于计算硬度的半经验模型,计算了该系列物质的硬度。其中,RhSi、FeGe和CoGe具有较高的弹性模量和较低的泊松比,具有成为超硬材料的潜质。     

Mg0.9M0.1Ni(M=Cr,Al,Ti,Zr)三元镁基储氢合金的制备及其电化学性能的研究

用机械合金化法成功地合成了Mg1.9M0.1Ni(M=Cr,Al,Ti,Zr),XRD结果表明,球磨80h后,Mg0.9M—Ni和Mg0.9Al0.1Ni合金已经完全非晶化．对此三元合金体系进行了电化学容量及循环寿命测试以及电化学交流阻抗(mS)测试．结果表明用这几种元素替代Mg后,合金电极的循环寿命有了明显的提高,但是其最高放电容易有所降低,抗腐蚀性能增强;该系列合金电极反应的速度控制步骤是由合金电解液界面间的电荷迁移和氢的扩散联合控制的．     

激光熔覆原位自生TiC增强Ni3(Si,Ti)金属间化合物复合涂层研究

运用激光熔覆技术在GH864镍基合金表面制备原位自生TiC颗粒,以增强Ni3(Si,Ti)金属间化合物复合涂层.实验结果表明:利用激光表面熔覆技术,可以在镍基合金表面直接原位合成TiC颗粒增强的Ni3(Si,Ti)金属间化合物复合涂层、涂层和基体呈良好的冶金结合,涂层宏观质量完好,无裂纹和气孔等缺陷.涂层组织由γ Ni、Ni3(Si,Ti)、Ni5Si2和TiC组成.涂层的显微硬度可达HV780,是基材显微硬度的2.5倍.     

尖晶石型MAl2O4(M=Ni、Mg)纳米粉体的溶胶凝胶法制备及表征

采用溶胶-凝胶法合成了MAl2O4（M=Ni、Mg）尖晶石纳米粉体，无水乙醇溶解摩尔比nM（NO3）2∶nM（NO3）3=1 ∶ 2，草酸作络合剂，加热搅拌得到湿凝胶，继续干燥得到干凝胶，随后对于凝胶在不同温度下进行焙烧，得到了粉体状产物．用TG、DSC技术对前躯体干凝胶进行热分析，对煅烧粉末进行了XRD、TEM表征，并考察了煅烧温度对MAl2O4晶化程度的影响．实验结果表明：该方法制备单相且晶化程度较高的尖晶石型MAl2O4纳米粉体所需温度为800℃，比微波反应法合成温度降低200℃，比铝单醇盐Sol-Gel法降低100℃．     

配合物[ML2]的合成及晶体结构(M=Ni2+,Cu2+;HL=C7H7NO)

标题化合物[ML2]（M=Ni^2-,Cu^2-;HL=C7H7NO,2-亚胺基甲基苯酚）由2-亚胺基甲基苯酚与NiCl2或CuCl2在无水乙醇中反应制得．用X射线衍射分析测定了两个化合物晶体结构．结果表明：它们均属单斜晶系,空间群为P2（1）／c,中心离子M（Ⅱ）的配位环境呈平面四方形．配合物[Ni（C7H6NO）2）]的晶体学参数：a=1．2918（3）nm,b=1．7512（4）nm,c=0．8110（2）nm,β=95．56（3）°,V=1．826（6）nm^3,Z=2,Dc=1．627Mg／m^3,Mr=298．97,μ=1．591mm^-1,F（000）=920,最终结构偏离因子R=0．0487,Ru=0．1199,S=1．018,最终差值电子云密度的最高峰和最低峰分别为1120nm^-3和-1226nm^-3配合物[Cu（C7H6NO）2）]的晶体学参数：a=1．2954（13）nm,b=0．5843（8）nm,c=0.8039（10）nm,β=94．69（3）°,V=0．6064（9）nm^3,Z=2,Dc=1．664Mg／m^3,Mr=303．80,μ=1．798mm^-1,F（000）=310,最终结构偏离因子R=0．0449,Rw=0．1196,S=1．077,最终差值电子云密度的最高峰和最低峰分别为484nm^-3和-388nm^-3．     

纳米金属酞菁MPc(M=Fe,Co,Ni,Cu和Zn)的合成与表征

采用溶剂热方法以邻苯二甲腈为原料、乙二醇为溶剂在反应釜中合成了各种形貌的Fe,Co,Ni,Cu和Zn纳米金属酞菁化合物,并对它们进行了电子扫描电镜、XRD、红外光谱及紫外-可见光谱表征.结果表明,产品纯度高,产率大,形貌独特.     

Polymerization of acrylonitrile catalyzed by lanthanide-sodium alkoxide clusters Lne（OCH2CH2NMe2）12（OH）eNas [Ln=Yb （1）, Nd （2） and Sm （3）]

Polymerization of acrylonitrile was carried out using,for the first time,the lanthanide-sodium alkoxide clusters Ln2(OCH2CH2NMe2)12(OH)2Na8 [Ln=Yb (1),Nd (2) and Sm (3)] as single component catalysts.These heterobimetallic complexes exhibit high activity and give atactic polyacrylonitriles with high molecular weight.The polymerization temperature can be varied over the range ?78 to 50°C.The solvent has a substantial effect on the polymerization activity.The order of activity for solvents is DMF>DME≈toluene≈...     

金属间化合物TM-Zn(TM=Ni,Pd,Pt,Cu,Ag,Au)四方变形结构稳定性的第一性原理研究

金属间化合物的结构和结构稳定性显著影响材料的性能. 本文基于第一性原理,利用“Exact Muffin-Tin Orbitals”(EMTO)方法及全电荷密度(Full Charge Density)处理技术,精确计算了TM10(Ni, Pd, Pt)-Zn和TM11(Cu, Ag, Au)-Zn两类金属间化合物体系能量,确定了体系的结构稳定性;使用“The Vienna ab initio package”(VASP)软件,采用投影缀加平面波赝势和PBE交换-关联泛函进行了全弛豫计算,模拟了TM-Zn金属间化合物的四方变形过程;通过分析金属间化合物在四方变形过程中电子态密度,揭示了其结构稳定性机理,并使用VESTA软件可视化了电子局域化函数,获得了金属键的特征;利用YPHON软件并结合线性响应理论计算了金属间化合物沿高对称点的声子色散曲线. 研究结果表明：TM10-Zn倾向于CuTi型结构稳定,而TM11-Zn倾向于CsCl型结构稳定;在费米能级附近的电子简并轨道劈裂,诱发TM10-Zn金属间化合物体系产生Jahn-Teller效应,Jahn-Teller效应使得其在四方变形过程中能量降低,因此其四方结构更加稳定,而在TM11-Zn金属间化合物体系并不存在Jahn-Teller效应,因此 CuTi型AgZn和AuZn结构不稳定;TM10-Zn的金属键强度大于TM11-Zn,且CsCl型结构的金属键强度大于CuTi型结构.     

Microstructure characterization and hydrogen storage properties study of Mg2Ni0.92M0.08 (M = Ti, V, Fe or Si) alloys

In the present study Mg_2Ni-type compounds alloyed independently with Ti,V,Fe and Si were successfully prepared by wet-milling followed by sintering.Although these alloyed Mg_2Ni compounds exhibited a similar hydrogen storage mechanism as that of pure Mg_2Ni,the dissolution of Ti,V or Fe into the Mg_2NiH_4lattice had a considerable catalytic effect on hydrogen desorption from additional MgH_2.The further structure investigations clearly indicated that the substitution of Ti for Ni could suppress the formation of the micro-twined low-temperature phase(LT2)and promote the formation of the high-temperature phase(HT),thus resulting in remarkably improved hydrogen desorption kinetics for the Mg_2Ni_(0.92)Ti_(0.08)–H system.     

锂离子电池负极材料M_2P_2S_6(M=Ni,Mn)的合成及电化学性能研究

通过室温固相法合成M2P2S6(M=Mn,Ni)层状结构材料,经XRD,SEM,EDS,IR和TG进行表征.结果表明,Mn2P2S6由粒径为40~50 nm的纳米球堆积而成,Ni2P2S6由不同大小粒子组成块状结构.将M2P2S6(M=Mn,Ni)作为锂离子电池负极材料进行电化学测试表明,M2P2S6(M=Mn,Ni)的首圈放电比容量分别高达800 m Ah/g和911 m Ah/g,说明M2P2S6化合物可能是一个潜在的锂离子电池负极材料.1     

氮、碳原子在X@Al_(12)(X=Al~-,C,Si,P~+)团簇吸附性质的研究

使用基于第一性原理的密度泛函理论(DFT)对X@Al12(X=Al",C,Si,P+)等幻数团簇吸附氮原子和碳原子性质进行研究.分析氮原子和碳原子在X@Al12表面的吸附位置,还分析了Al-N和Al-C键长,最高占据分子轨道与最低未占据分子轨道的能隙,吸附的结合能和电荷转移等性质.结果表明氮原子和碳原子都倾向于空位吸附.尽管X@Al12(X=Al-,C,Si,P+)性质都很稳定,但很大的结合能表明氮原子和碳原子都能稳定地束缚在这些团簇表面.但是由于中性的Al13团簇不具有满壳层的电子结构,它对N和C的吸附性质明显不同于具有满壳层电子结构的X@Al12(X=Al-,C,Si,P+)团簇,表明掺杂可以有效地调节团簇的性质,从而获得所期望的性质.