二维M_2XO_(2-2x)(OH)_(2x)(M=Ti,V;X=C,N)析氢催化活性的第一性原理研究

MXene是一种新型的二维析氢催化材料,其表面容易被亲水基团O和OH混合覆盖。我们基于第一性原理计算的方法,研究了M_2XO_(2-2x)(OH)_(2x)(M=Ti,V;X=C,N)的析氢催化活性。计算结果显示,M_2XO_(2-2x)(OH)_(2x)的析氢催化活性与其表面OH覆盖率(X)密切相关。对Ti_2CO_(2-2x)(OH)_(2x)来说,OH覆盖率不超过1/3时,具有优异的析氢催化活性。对Ti_2NO_(2-2x)(OH)_(2x)、V_2CO_(2-2x)(OH)_(2x)和V_2NO_(2-2x)(OH)_(2x)来说,OH覆盖率分别达到4/9、1/3和5/9时,才具有最佳的析氢催化活性。接着,电荷分析显示OH覆盖率会显著影响M_2XO_(2-2x)(OH)_(2x)活性位点O基团的电荷量。最后,我们从态密度的角度揭示了析氢催化活性变化的原因,即活性位点O基团的氧化性随OH覆盖率的增大而被削弱。因此,本文提出了调节表面OH覆盖率来获取M_2XO_(2-2x)(OH)_(2x)最佳析氢催化活性状态的方法,这在工业制氢生产过程中具有重要的应用价值。     

La0.7-xDyxSr0.3MnO3(0.00≤x≤0.70)的TCR研究

研究了La位Dy掺杂对La0.7-xDyxSr0.3MnO3(0.00≤x≤0.70)电阻温度系数(TCR)的影响.实验结果表明:Dy掺杂将引起电阻率曲线的急剧变化,导致出现大的TCR;随Dy掺杂的增加,TCR在x=0.30出现峰值,然后随掺杂量的增加逐步降低.体系出现大的TCR,来源于Dy掺杂引起的晶格畸变和额外磁性耦合.     

Thermal Properties of K（Y1-xYbx）（WO4）2（x=0.098,0.196,0.294） Crystal

Thermal properties of pure KY(WO4)2 and K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were investigated.The specific heat and thermal diffusivity of crystals were calculated at a range of 50～300 ℃.The calculated result shows that the specific heat and thermal diffusivity of K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were slightly affected by the Yb3+ concentration.The thermal expansion coefficient of K(Y0.804Yb0.196)(WO4)2 crystals along x,y and z axes were determined to be 13.51,4.474 and 16.60×10-6 K-1,respectively.These results suggest the K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystal as a laser crystal of low-middle power.     

钙掺杂对La2-xCaxCe2O7-δ性能影响研究

利用高温固相反应法制备了高温质子导体La2-xCaxCe2O7-δ(0≤x≤0.2)。分别利用X射线衍射(XRD)、扫描电子显微镜(SEM)对试样的相组成、微观形貌进行了表征。并对试样在水蒸气和CO2气氛中的化学稳定性进行了测试。研究了不同掺杂量和不同测试气氛对La2-xCaxCe2O7-δ电性能的影响。实验结果表明:1 500℃烧结的试样均形成萤石型结构;试样在CO2和水蒸气气氛中表现出良好的化学稳定性。试样在湿润氢气气氛下的电导率明显高于干燥空气气氛,x=0.1的试样在湿润氢气气氛中具有最高的电导率,850℃时达到3.16×10-2S.cm-1,电导活化能为84.93 kJ.mol-1。     

Co~(2+)/Cd~(2+)复合材料的合成及其催化性质（英文）

在相同的反应条件下,基于配体(Hpypymba=4-((3-(吡嗪-2-基)-1H-吡唑-1-基)甲基)苯甲酸)和过渡金属离子(Co(Ⅱ)、Cd(Ⅱ))合成同构金属掺杂材料[Co_xCd_(1-x)(pypymba)_2]_n(0≤x≤1)(配合物1～5),运用粉末X射线衍射(PXRD)、紫外等分析手段对其结构与形貌进行表征。将得到的MOFs作为催化剂载体负载Ag离子进行4-硝基苯酚的还原反应。研究表明含Co~(2+)的化合物1是良好的催化剂载体,随着配合物中Cd~(2+)比例的增加,反应速率下降,甚至对反应有一定的抑制效果。该MOFs对于Ag的最大负载量为47%(w/w),Ag@compound 1经4次循环后依然有96%的催化效率。     

白色荧光粉KCaY_(1-x)(PO_4)_2:xDy~(3+)的制备及真空紫外发光特性

一种新型具有六方晶系的KCaY_(1-x)(PO_4)_2:xDy~(3+)(0x≤0.10)白色荧光粉采用固相法被成功合成,研究了其在真空紫外激发下的发光特性。结果表明,在147 nm激发下,样品主要呈现472 nm的蓝色和578 nm的黄色发射,在578 nm监控下的激发光谱表明基质和激活离子间存在着一定的能量转移现象,因此通过固相反应制备的单一体系单一激活离子的白色荧光粉KCaY_(1-x)(PO_4)_2:xDy~(3+)(0x≤0.10)将在无汞荧光灯上有潜在的应用价值。     

SO~(2-)_4掺杂对Nasicon型Li_3Fe_2(PO_4)_3正极材料电化学性能的影响

采用溶胶-凝胶法用SO~(2-)_4部分代替Li_3Fe_2(PO_4)_3中的PO~(3-)_4阴离子制得Li_(3-x)Fe_2(PO4)_(3-x)(SO_4)_x(x=0~0.90)正极材料,通过X射线衍射、充放电技术、循环伏安特性测试及电化学阻抗谱表征了掺杂材料的相组成及电化学性能.结果表明,SO~(2-)_4主要以固溶形式存在于Li_3Fe_2(PO_4)_3中,产物中还伴有少量Fe_2O_3第二相析出.SO~(2-)_4掺杂使Li_3Fe_2(PO_4)_3的放电容量呈抛物线形规律变化,并在掺杂浓度x=0.60时达到最佳值,该样品在0.5C倍率下的首次放电容量为111.59 mA·h/g,比未掺杂的样品提高了18.4%;60次循环充放电后的容量保持率为96%;将该样品的放电倍率由0.5C逐渐提高至5C,再降至0.5C,并在每个倍率下循环10次,材料的最终放电容量仍能达到首次放电容量的97%.导致这些变化的原因是SO~(2-)_4掺杂使材料的氧化还原性能增强,电池内阻减小,极化程度降低及Li~+扩散系数增大.     

Na_（1＋x）Al_xZr_（2－x）P_3O_（12）的水热合成与表征

采用水热法合成了系列磷酸盐化合物Ｎａ_（１＋ｘ）Ａｌ_ｘＺｒ_（２－ｘ）Ｐ_３Ｏ_（１２），该系列化合物具有ＮＡＳＩＣＯＮ型三维骨架结构。考查了反应物料配比、晶化时间、晶化温度等实验条件对产物物相及掺入Ａｌ含量对化合物的结构与性能的影响．实验结果表明：在０≤ｘ≤０．３３的范围内，可水热合成出Ｎａ_（１＋ｘ）Ａｌ_ｘＺｒ_（２－ｘ）Ｐ_３Ｏ_（１２）纯相，而且具有良好的热稳定性。该系列化合物的离子电导率测试结果表明，其电导率与掺入的Ａｌ含量有关。     

新型固体电解质Ce6- x Sm x MoO15- δ (0≤x≤1.2)的合成及电性质

采用溶胶-凝胶方法合成系列新型氧化物 Ce6- x Sm x MoO15- δ (0≤x≤1.2). 通过TG-DTA, XRD和XPS等手段对氧化物结构进行了表征. 结果表明, 氧化物的最低成相温度为400 ℃, 具有立方莹石结构. Sm的掺杂可增加氧离子空位浓度, 改善母体电导率. 阻抗谱表明, 采用溶胶-凝胶法合成固体电解质可减少或消除其晶界电阻. 800 ℃时, Ce5.2Sm0.8MoO15- δ的电导率高达6.67×10-3 S/cm.     

Li_2SO_4-MgSO_4、Li_2SO_4-Li_4SiO_4体系的研究

本文用X射线衍射(高温、室温)相热分析(DTA、DSC、TGA)等方法测定了Li_2SO_4-MgSO_4和Li_2SO_4-Li_4SiO_4体系相图,并研究了化合物的性能和晶体结构. Mg_4Li_2(SO_4)_5在840℃由包晶反应形成,它在105℃分解为Li_2SO_4为基的固溶体和MgSO_4.在105℃反应时,形成每摩尔的Mg_4Li_2(SO_4)_5吸热2.57kJ,反应激活能为173.5kJ/mol.Mg_4Li_2(SO_4)_5属正交晶系,在180℃的点阵常数α=8.577A,b=8.741A,c=11.918A,可能的空间群为.P222或Pmmm,Z=2. Li_(8-2x)(SiO_4)_(2-x)(SO_4)_x是在953℃由包晶反应形成的新相.随着温度的降低,相区扩大.在室温x=0.96—0.58.该相属正交晶系,空间群为.Pmmm,Z=2.晶体的点阵常数在x=0.8时有一最大值,α=5.002A,b=6.173A,c=10.608A.Li_(8-2x)(SiO_4)_(2-x)(SO_4)_x在空气中能吸收7.6wt％的水蒸气和其他气体.脱水温度高于350℃,水份的吸脱不改变晶体结构,与沸石分子筛具有相似性质,脱水激活能为171.5kJ/mol. 熔化后的Li_2SO_4-MgSO_4和Li_2SO_4-Li_4SiO_4试样以10℃/min速率降温,分别形成亚稳态共晶体系.     

STRUCTURE OF [W(H)_2(F)(OH_2)(PMe_2)_4]F

<正> Mr = 546.3, orthorhombic, space group Cmc21, a = 14.223(4), b = 12.907(3), c = 12.343(4) A, V = 2265.746 A3, Z = 4, DC = 1.601 Mg.m-3, λ= 0.7106 A, μ(MoK(?)) = 56.86 cm-1, F(OOO) = 1048. Final R = 0.044 for 1937 observed reflections. Cation [W(H)2(F)(OH2)(PMes)4]4 has a mirror symmetry, an equatorial belt of four PMe3 groups and mutually syn fluoride and water Ugands. The mean W-P length is 2.462 (A) and P-C 1.83 (A). From the dimensions of the metal, fluoride and water system ( W(1)-F(1) = 2.08(1), W(1)-0(1) - 2.084(9), F(2)-O(1) = 2.59(2) A and F(2)-W(1)-O(1) - 76.7(4)°) an in-terligand hydrogen bond was assumed. The ligand water molecule also makes an H-bonded contact with the fluoride counter ion.     

CRYSTAL STRUCTURE OF Pt（dppe）（SPh）2

<正> Anaerobic reaction of Pt (dppe)Cl2 (dppe = Ph2PCH2CH2PPh2) with NaSPh and elemental selenium affords complex Pt(dppe)(SPh)2,which crystallizes in the monoclinic system space group C2/c with a=14. 392(7) ,b=16. 380(7) ,c=14. 266(5) A ,β=86. 44(4)°,V=3342(5) A3,Z = 4,Dc=1. 613g/cm3,and μ(MoKa) = 44. 813 cm-1. The final structural refinement converged with unweighted and weighted R factors of 0. 041 and 0. 057 for 2206 observed reflections (I>3σ(I)). X-ray analysis shows that the Pt atom in Pt(dppe)(SPh)2 is at the center of the approximately planar tetragon of two P atoms and two S atoms.     

Ca(1)(-)(x)Na(2)(x)Al(2)B(2)O(7): a structure with tunable density of Na(+) vacancies

A series of samples with the composition Ca(1)(-)(x)Na(2)(x)Al(2)B(2)O(7) (0 < x < or = 1) was investigated and a hexagonal structure with unusually large range of homogeneity (at least from x = 0.01 to 0.95) was revealed. The hexagonal phase consists of [Al(2)B(2)O(7)](infinity)(2)(-) lamellae stacked along the c axis, as in CaAl(2)B(2)O(7) and Na(2)Al(2)B(2)O(7). Nevertheless, the configuration and stacking sequence of the [Al(2)B(2)O(7)](infinity)(2)(-) lamellae are different in these three structures. In the hexagonal structure of Ca(1)(-)(x)()Na(2)(x)()Al(2)B(2)O(7), Ca and half Na cations (Na1) statistically occupy the same crystallographic site which is located between the [Al(2)B(2)O(7)](infinity)(2)(-) lamellae, the other half Na cations (Na2) distribute in the planes bisecting the [Al(2)B(2)O(7)](infinity)(2)(-) lamellae. Depending on the composition, the site occupation factor of Na2 site can vary in the same range as x, leading to a tunable density of Na(+) vacancies in the structure. The AlO(4) tetrahedra and BO(3) triangles in the structure tilt in appropriate ways to improve the bond valence sum of Na2 cations which are not sufficiently bonded to the anions.     

The extraction of Zn(II), Cd(II) and Pb(II) from hydrochloric acid media by amberlite LA-2 hydrochloride dissolved in 1,2-dichloroethane

The extraction of HC1 by the secondary amine (B), known as Amberlite LA-2, dissolved in 1,2-dichloroethane and the aggregation of BHC1 have been studied by using a two-phase potentiometric titration technique. The experimental data, treated by a general minimizing program, indicate dimerization: 2 BHClright harpoon over left harpoon(BHCl)(2). The equilibrium constant of this reaction was calculated. The extraction of ZnCl(2), CdCl(2) and PbCl(2) from 0.2,0.5, 1.0 and 2.0M HCl, and 1MNaCl by Amberlite LA-2 hydrochloride (BHCl), dissolved in 1,2-dichloroethane, has been studied. The complexes (BHCl)(2)ZnCl(2), (BHCl)(2)CdCl(2) and (BHCl)(2)PbCl(2) were found to exist, irrespective of the composition of the aqueous phase. The formation constant of the first was calculated.     

[(O)MoCu_3(μ_3-S)_3(μ_3-Cl)(PPh_3)_3]·2THF的合成及其晶体结构

固体化合物(NH_4)_6Mo_7O_(24)·4H_2O和(PPh_3)_2CuCl与饱和液体NH_4HS反应获得桔红针状标题晶体。晶体空间群为P2_1/c,晶胞参数a=11.742(2),b=28.186(7),c=19.304(3),β=100.57(2)°,V=6280.4(?)~3,D_c=1.46g/cm~3,Z=4,F(000)=2816。在3≤2θ≤45°范围内收集到8414个独立衍射强度数据,其中3856个I≥1.5σ(I)强度数据参加结构计算。标题化合物分子是以{MoCu_3S_3Cl}类立方烷型簇为核心的分子,Mo—Cu的平均距离为2.716。     

CRYSTAL STRUCTURE OF FeaTe_2(CO)_6(NO)(η_5-C_5H_5)

<正> The title compound belongs to triclinic system, space group PI, with dimensions: a = 9.237(1), b = 9.589(1), c = 10.424(1) A ; <*= 72.09(2)?ft- 88.79(2)? 3r=80.28(l)? Z = 2, V = 865.5 A3, Dx = 2.626 gcnr3. Final R = 0.026 and Rw = 0.036 for 2531 reflections.     

Synthesis and Crystal Structure of LanthanideHetero-polymolybdate Complex:(NH_4)_(12)H_(10)〔Nd_4Mo_(29)O_(104)(H_2O)_(12)〕·22H_2O

11NTRODUCTIoNNowadaysheteropoly-complexesaremorenoticeableespeciallyinthefieldofcat-alystbecauseinsomeorganicsynthesestheycanbeusedasanoxidativetypeoracidictypecatalystorasboth.Ontheotherhandtherearemanytheoreticaltopicsaboutheteropolycomplexinwhichmanyscientistsareinterested.Inthefieldofpolyacidchemistrythesynthesisofanewheteropolycomplexisanimportantaspect.Molybdenumcanformbinaryheteropolymolybdatecomplexcompoundswithmanymetalandnon-metalelements.Indifferentcompoundstheratioofheteroatoms…     

Alloyed (ZnS)(x)(Cu2SnS3)(1-x) and (CuInS2)(x)(Cu2SnS3)(1-x) nanocrystals with arbitrary composition and broad tunable band gaps

Cu(2)SnS(3) nanocrystals with metastable zincblende and wurtzite structures have been successfully synthesized for the first time. Alloyed (ZnS)(x)(Cu(2)SnS(3))(1-x) and (CuInS(2))(x)(Cu(2)SnS(3))(1-x) nanocrystals with arbitrary composition (0 ≤x≤ 1) and ultra-broad tunable band gaps (3.63 to 0.94 eV) were obtained.     

Crystal Structure of[Ru(taab)(DMF)_2]·[(CIO_4)_2]

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ［Ｒｕ（ｔａａｂ）（ＤＭＦ）_２］·［（ＣＩＯ_４）_２］￥ＤｕａｎＣｈｕｎ－Ｙｉｎｇ；ＬｕＺｈｏｎｇ－Ｌｉｎ；ＴｉａｎＹｕ－Ｐｅｎｇ；ＹｏｕＸｉａｏ－Ｚｅｎｇ；ＣｈｅｎＹａｏ（ＣｏｏｒｄｉｎａｔｉｏｎＣｈｅｍｉｓｔ?..     

CRYSTAL STRUCTURE OF TRINUCLEAR MOLYBDENUM CLUS-TER Mo_3(μ_3-S)(μ_2-S_2)_3(Et_2dtc)_3I SYNTHESIZED BY SOLID STATE REACTION

<正> The title cluster compound was synthesized by solid state reaction at low heating temperature. C15H30IMo3N3S13, Mr=1083. 93, monoclinic, P21/n, a = 14.396(3), b = 13. 116(3), c=18. 142(8)A;β= 91. 36(3)°; V =3425(2)A3, Z = 4. Dc = 2. 10g/cm3, F(000) = 2112,μ(MoKa) = 27. 29cm-1, final R = 0. 034, Rw = 0. 051 for 1845 unique observed reflections (I≥3σ(I)). The three Mo atoms form an equilateral triangle with an average side length of 2. 714 A. Each Mo atom is coordinated with seven S atoms forming a distorted pentagonal bipyramid. The iodine atom connects with three S atoms (out of the CMo3] plane) with an average distance of 3. 205 A.The title compound has similar cubane-like cluster core [Mo3S7I] as the compound Mo3(μ3-S)(μ2-S2)3(dtp)3I(dtp= (EtO)2PS2).