An approach to the synthesis of polyoxometalate encapsulating different kinds of oxoanions as heteroions: bisphosphitopyrophosphatotriacontamolybdate [(HPO3)2(P2O7)Mo30O90]8-

A yellow [(HPO(3))(2)(P(2)O(7))Mo(30)O(90)](8-) anion was prepared as a tetrapropylammonium (Pr(4)N(+)) salt from a 50 mM Mo(VI)-2 mM P(2)O(7)(4-)-4 mM HPO(3)(2-)-0.95 M HCl-60% (v/v) CH(3)CN system at ambient temperature. The (Pr(4)N)(8)[(HPO(3))(2)(P(2)O(7))Mo(30)O(90)] salt crystallized in the orthorhombic space group P(nma) (No. 62), with a = 30.827(2) A, b = 22.8060(15) A, c = 30.928(2) A, V = 21743(3) A(3), and Z = 4. The structure contained a (P(2)O(7))Mo(12)O(42) fragment derived from the removal of each corner-shared Mo(3)O(13) unit in a polar position from a [(P(2)O(7))Mo(18)O(54)](4-) structure, and each side of the (P(2)O(7))Mo(12)O(42) fragment was capped by a B-type (HPO(3))Mo(9)O(24) unit. The [(HPO(3))(2)(P(2)O(7))Mo(30)O(90)](8-) anion was characterized by voltammetry and IR, UV-vis, and (31)P NMR spectroscopy. Unlike the Keggin and Dawson anions and the parent [(P(2)O(7))Mo(18)O(54)](4-) anion, the [(HPO(3))(2)(P(2)O(7))Mo(30)O(90)](8-) anion exhibited two-electron redox waves in CH(3)CN with and without acid.     

Quantitative determination of the speciation of surface vanadium oxides and their catalytic activity

A quantitative method based on UV-vis diffuse reflectance spectroscopy (DRS) was developed that allows determination of the fraction of monomeric and polymeric VO(x) species that are present in vanadate materials. This new quantitative method allows determination of the distribution of monomeric and polymeric surface VO(x) species present in dehydrated supported V(2)O(5)/SiO(2), V(2)O(5)/Al(2)O(3), and V(2)O(5)/ZrO(2) catalysts below monolayer surface coverage when V(2)O(5) nanoparticles are not present. Isolated surface VO(x) species are exclusively present at low surface vanadia coverage on all the dehydrated oxide supports. However, polymeric surface VO(x) species are also present on the dehydrated Al(2)O(3) and ZrO(2) supports at intermediate surface coverage and the polymeric chains are the dominant surface vanadia species at monolayer surface coverage. The propane oxidative dehydrogenation (ODH) turnover frequency (TOF) values are essentially indistinguishable for the isolated and polymeric surface VO(x) species on the same oxide support, and are also not affected by the Br?nsted acidity or reducibility of the surface VO(x) species. The propane ODH TOF, however, varies by more than an order of magnitude with the specific oxide support (ZrO(2) > Al(2)O(3) > SiO(2)) for both the isolated and polymeric surface VO(x) species. These new findings reveal that the support cation is a potent ligand that directly influences the reactivity of the bridging V-O-support bond, the catalytic active site, by controlling its basic character with the support electronegativity. These new fundamental insights about polymerization extent of surface vanadia species on SiO(2), Al(2)O(3), and ZrO(2) are also applicable to other supported vanadia catalysts (e.g., CeO(2), TiO(2), Nb(2)O(5)) as well as other supported metal oxide (e.g., CrO(3), MoO(3), WO(3)) catalyst systems.     

空心球形In2O3/ZrO2-TiO2纳米复合材料多模式光催化

本文以聚苯乙烯(PS)胶球为模板,通过一步水浴法结合煅烧后处理制备了不同比例的In_2O_3/ZrO_2-TiO_2空心球状复合材料(简写为In_2O_3/ZrO_2-TiO_2-H)。通过X-射线衍射、扫描电镜、X-射线光电子能谱、紫外-可见漫反射吸收光谱和氮气吸附-脱附等测试手段对该系列复合材料的结构、组成和形貌进行了表征。结果表明,In_2O_3/ZrO_2-TiO_2复合材料经PS模板处理后呈现空心球状结构,球壁由纳米粒子堆积而成。将In_2O_3与ZrO_2-TiO_2复合后其光吸收性能呈现了一定的红移现象,且In_2O_3/ZrO_2-TiO_2-H(1∶4)的比表面积较大(66.92m~2·g~(-1))。同时,为了考察该复合材料的光催化性能,在多模式光催化条件下对甲基橙的降解情况进行了研究。结果表明,In_2O_3/ZrO_2-TiO_2-H(1∶4)表现出较好的光催化性能,其光催化活性高于P25、ZrO_2、In_2O_3/ZrO_2-TiO_2及其他体积比的In_2O_3/ZrO_2-TiO_2-H。     

Pyrophosphate Complexation of Tin(II) in Aqueous Solutions as Applied in Electrolytes for the Deposition of Tin and Tin Alloys Such as White Bronze

Electrodeposition of tin and tin alloys from electrolytes containing tin(II) and pyrophosphates is an important process in metal finishing, but the nature of the tin pyrophosphate complexes present in these solutions in various pH regions has remained unknown. Through solubility and pH studies, IR and (31)P and (119)Sn NMR spectroscopic investigations of solutions obtained by dissolving Sn(2)P(2)O(7) in equimolar quantities of either Na(4)P(2)O(7)·10H(2)O or K(4)P(2)O(7) the formation of anionic 1:1 complexes {[Sn(P(2)O(7))]}(n)(2n-) has now been verified and the molecular structures of the monomer (n = 1) and the dimer (n = 2) have been calculated by density functional theory (DFT) methods. Whereas the alkali pyrophosphates Na/K(4)P(2)O(7) give strongly alkaline aqueous solutions (pH ～13), because of partial protonation of the [P(2)O(7)](4-) anion, the [Sn(P(2)O(7))](2-) anion is not protonated and the solutions of Na/K(2)[Sn(P(2)O(7))] are almost neutral (pH ～8). The monomeric dianion appears to have a ground state with C(2v) symmetry with the Sn atom in a square pyramidal coordination and the lone pair of electrons in the apical position, while the dimer approaches C(2) symmetry with the Sn atoms in a rhombic pyramidal coordination, also with a sterically active lone pair. A comparison of experimental and calculated IR details favors the monomer as the most abundant species in solution. With an excess of pyrophosphate, 3:2 and 2:1 complexes (P(2)O(7)):(Sn) are first formed, which, in the presence of more pyrophosphate, undergo rapid ligand exchange on the NMR time scale. The structure of the 2:1 complex [Sn(P(2)O(7))(2)](6-) was calculated to have a pyramidal complexation by two 1,5-chelating pyrophosphate ligands. Neutralization of these alkaline solutions by sulfuric or sulfonic acids (H(2)SO(4), MeSO(3)H), as also practiced in electroplating, appears to afford the tin(II) hydrogen pyrophosphates [Sn(P(2)O(7)H)](-) and [Sn(H(2)P(2)O(7))](0). The molecular structures of the mononuclear model units have also been calculated and were shown to have an unsymmetrical complexation and to feature trigonal pyramidal (pseudotetrahedral) coordination. NMR observations have shown that, contrary to the results obtained for Sn(II) compounds, Sn(IV) as present in K(2)SnO(3) or its hydrated form (K(2)Sn(OH)(6)) does not form a pyrophosphate complex in aqueous solution near pH 7. There is also no interference of sulfite.     

Ni／ZrO2-Al2O3制备表征及催化性能的研究

本文采用浸渍沉淀法制备了不同配比的ZrO2-Al2O3复合载体。并通过浸渍法制备Ni/ZrO2-Al2O3催化剂,以苯加氢制环己烷反应为探针,考察了ZrO2与Al2O3的配比对Ni催化剂催化加氢性能的影响;采用X射线衍射(XRD)、程序升温还原(TPR)、程序升温脱附(TPD)等技术考察复合载体对Ni催化剂的体相结构、还原性能以及表面吸附性能的影响。研究结果表明,ZrO2质量分数为20%的复合载体所负载的Ni催化剂有很好的加氢活性,优于单组分载体负载的Ni催化剂;采用浸渍沉淀法制备的ZrO2-Al2O3复合载体中ZrO2以非晶态形式存在,这是由于Al2O3的存在影响了ZrO2的内部结构;该载体负载的Ni催化剂较其他催化剂更容易被还原,吸附中心数量增加。     

脉冲电沉积制备HA/ZrO2纳米复合涂层的稳定性及生物相容性评价

采用脉冲电化学沉积法成功地在生物医用钛金属表面制备出均匀的纳米HA/ZrO₂复合涂层. 通过热处理提高涂层的致密性, 同时保留涂层的微纳结构. 考察了热处理后复合涂层的成分、形貌、生物相容性及生理稳定性. X射线衍射分析表明, 复合涂层成分为HA和ZrO₂. 扫描电镜观察发现, 热处理后复合涂层的致密性有所提高. 研究发现, ZrO₂的加入大大降低了HA/ZrO₂复合涂层中钙离子的释放速度, 提高了HA/ZrO₂复合涂层的生理稳定性. 纳米划痕实验结果表明, HA/ZrO₂复合涂层具有较好的结合强度. 通过培养成骨细胞考察了复合涂层的生物相容性. Alamar Blue检测表明, HA/ZrO₂复合涂层表面细胞黏附及增殖能力较好. ALP检测发现, 热处理后HA/ZrO₂复合涂层表面的细胞分化能力较强. 综合细胞培养结果显示, HA/ZrO₂复合涂层有较好的生物相容性.     

制备方法对负载型纳米ZrO2/Al2O3复合载体性能的影响

采用浸渍-沉淀法制备了负载型纳米ZrO2/Al2O3复合载体.采用X射线衍射、N2物理吸附、差示扫描量热(DSC)和程序升温脱附等技术考察了浸渍方式和干燥方法对复合载体的表面性能、热稳定性和晶相结构的影响.结果表明,ZrO2/Al2O3复合载体中没有生成ZrO2-Al2O3复合氧化物或固溶体,纳米ZrO2仅负载在Al2O3的表面.微波干燥法制备的ZrO2/Al2O3复合载体的比表面积(158.7 m2/g)较大,最可几孔径为19.4 nm,ZrO2的粒度为4.2 nm,晶相结构为四方相ZrO2.微波诱导作用使ZrO2/Al2O3复合载体表面产生了新的酸碱中心,微波干燥法制备的ZrO2/Al2O3复合载体具有较强的热稳定性,在873~1 073 K范围内DSC曲线没有出现吸热峰,而其它干燥方法制备的复合载体在903~1 023 K范围内出现了较明显的吸热峰,表明复合载体表面的部分四方相ZrO2转变为单斜相ZrO2(m-ZrO2).对超声波处理过的复合载体进行微波干燥能进一步提高纳米ZrO2与Al2O3之间的相互作用,纳米粒子的粒度(3.4 nm)更小,分布更均匀,但没有改变ZrO2的晶相结构.     

Synthesis and characterization of a novel organically templated open framework zirconogermanate with three- and seven-membered rings

A new organically templated microporous zirconogermanate, (C(2)H(10)N(2))H(2)O[ZrGe(3)O(9)] (denoted as FDZG-3), with a low framework density of 13.6 T/1000 A(3), has been solvo/hydrothermally synthesized by using ZrO(NO(3))(2).2H(2)O as a zirconium source and triethylenetetramine (TETA) as a structure direct agent. This compound was characterized by means of single-crystal X-ray diffraction analysis, thermogravimetrical analysis, and IR and UV-vis spectra. Its three-dimensional (3D) framework is built up by 1D sinusoidal germanate chains cross-linked by ZrO(6) octahedra, which forms a network containing three- and seven-membered rings (MRs). Four intersecting 7-MR channels can be observed along the b axis, c axis, [110], and [-110] directions, respectively. Charge-balancing (C(2)H(10)N(2))(2+) and extraframework water molecules are encapsulated within 7-MR channels and form hydrogen bonds with framework oxygen atoms. Crystal data for FDZG-3: M = 533.13, monoclinic, space group Cc (No.9), a = 11.299(3) A, b = 7.7649(19) A, c = 13.835(3) A, beta = 104.826(3) degrees, V = 1173.4(5) A(3), Z = 4, R1 = 0.0263, wR2 = 0.0529.     

Colorimetric detection of Fe3+ ions using pyrophosphate functionalized gold nanoparticles

A sensitive, selective colorimetric Fe(3+) detection method has been developed by using pyrophosphate functionalized gold nanoparticles (P(2)O(7)(4-)-AuNPs). Gold nanoparticles were prepared by reducing HAuCl(4) with sodium borohydride, in the presence of Na(4)P(2)O(7). IR spectra suggested that pyrophosphates were capped on the surface of the gold nanoparticles. Aggregation of P(2)O(7)(4-)-AuNPs was induced immediately in the presence of Fe(3+) ions, yielding a color change from pink to violet. This Fe(3+)-induced aggregation of P(2)O(7)(4-)-AuNPs was monitored using first the naked eye and then UV-vis spectroscopy with a detection limit of 5.6 μM. The P(2)O(7)(4-)-AuNPs bound by Fe(3+) showed excellent selectivity compared to other metal ions (Ca(2+), Cd(2+), Co(2+), Fe(2+), Hg(2+), K(+), Mg(2+), Mn(2+), Na(+), Ni(2+), Pb(2+), and Zn(2+)). The best detection of Fe(3+) was achieved in a pH range from 3 to 9. In addition, the P(2)O(7)(4-)-AuNPs were also used to detect Fe(3+) in lake water samples, with low interference.     

ZrO2负载量对负载型纳米ZrO2/Al2O3复合载体的结构及性能影响

ZrO2在基载体Al2O3表面存在分散阈值(0.242 g/gAl2O3).在ZrO2/Al2O3复合载体中,ZrO2负载量不同其分布和粒度大小不同,当ZrO2负载量在0.242 g/gAl2O3-0.60 g/gAl2O3的范围内,ZrO2/Al2O3复合载体中纳米ZrO2的粒子的大小保持在4.2 nm,且单层分布在Al2O3的表面.当ZrO2负载量大于0.60 g/gAl2O3时,纳米粒子的粒径增大,并出现多层分布或堆积.XRD、DSC、HRTEM、XPS、H2-TPR结果表明,随着ZrO2负载量增大,复合载体中纳米ZrO2的分布由单层分布转化为多层或堆积分布,ZrO2负载量为0.60 g/gAl2O3时复合载体表面积最大(164.3 m2/g),ZrO2负载量的继续提高,复合载体的表面积明显下降.     

二氧化硅修饰纳米氧化锆陶瓷材料的制备及性能

以二甲基二乙氧基硅烷为硅源,在水溶液中成功制备了SiO2修饰纳米ZrO2颗粒;利用透射电子显微镜、热重分析仪、X射线衍射仪、红外光谱仪分析了样品的形貌和结构;将SiO2/ZrO2与α-Al2O3制成陶瓷材料,考察了其机械性能.结果表明,所制备的SiO2/ZrO2晶粒均一,直径约为10nm,硅原子在SiO2/ZrO2中以Si―O―Zr键合形式存在,SiO2不影响ZrO2的晶型.引入SiO2使得ZrO2晶粒细化、尺寸均匀性提高;SiO2/ZrO2/Al2O3陶瓷气孔率小,具有致密的显微结构和优异的机械性能.     

Proton conduction in indium hydrogensulfate and hydrous zirconia composites

Solid composite proton electrolytes based on indium hydrogensulfate and hydrous zirconia are studied. A composite effect is observed in these systems: their proton conductivity is higher than in the starting components. Maximal conductivities are achieved at a comparatively low concentration of hydrous zirconia (10% wt %) in composites heat-treated at 373 K. The increasing surface basicity of hydrous zirconia as a result changing its deposition pH noticeably improves the low-temperature conductivity of the composites. Irreversible processes that decrease the conductivity occur in composites even during treatment at temperatures above 373 K. A third component (neutral indium sulfate) only decreases the conductivity.     

α-Al2O3纳米粒子对Co-Ni合金异常共沉积电化学行为的影响

为了研究在电化学复合共沉积过程中,惰性纳米粒子和金属离子、电极表面的相互作用,以及由此产生的对合金电化学共沉积行为的影响.本文从两个吸附过程出发: 电解液中的金属离子和H＋在纳米粒子表面的吸附；纳米粒子迁移到阴极表面,在电极表面的吸附.采用Zeta电势和稳态极化以及电化学交流阻抗（EIS）研究了纳米Al2O3粒子和电解液中的金属离子，和电极表面的相互作用,进而分析了纳米粒子对Co2＋和Ni2＋还原沉积的影响规律.通过对阻抗数据的拟合,讨论了Al2O3纳米粒子对等效电路中各物理参数的影响.在H＋和不同金属离子在纳米粒子上发生竞争吸附的基础上,提出了纳米粒子和合金共沉积的可能反应历程.     

Cation mobility and kinetics of ion exchange in zirconium hydrogen monothiophosphate hydrate, Zr(HPO(3)S)(2)x1.5H(2)O

The ion conductivity of zirconium hydrogen monothiophosphate (Zr(HPO(3)S)(2)x1.5H(2)O) has been measured by impedance spectroscopy. The measured value of proton conductivity is 3 x 10(-5) S/cm at 298 K. Conductivity was shown to decrease with increasing temperature due to a dehydration process. Above 450 K, the conductivity is likely governed by proton transport in the anhydrous phase Zr(HPO(3)S)(2). The activation energies of proton conductivity were measured to be 18 +/- 2 kJ/mol for Zr(HPO(3)S)(2)x1.5H(2)O and 60 +/- 3 kJ/mol for the anhydrous compound. The kinetics of ion exchange was studied with the use of potentiometric titration for several ion pairs, H(+)/Na(+), H(+)/Zn(2+), and Na(+)/Zn(2+) in Zr(HPO(3)S)(2)x1.5H(2)O. The diffusion coefficient values for H(+)/Na(+) ion exchange in Zr(HPO(3)S)(2)x1.5H(2)O are lower than those reported in alpha-zirconium phosphate. At the same time, the mobility of zinc ions in Zr(HPO(3)S)(2)x1.5H(2)O is higher than sodium ion mobility. The ion exchange H(+)/Zn(2+) is accompanied by the slow hydrolysis of the initial compound. In all cases, the powdered solids were evaluated by powder X-ray diffraction, and particle sizes were controlled by grinding and sieving the powders.     

负载型纳米ZrO2-Al2O3复合载体中ZrO2的负载量对Ni基催化剂性能的影响

采用真空浸渍法在负载型纳米ZrO2-Al2O3复合载体上负载NiO,并用X射线衍射考察了NiO在复合载体上的分散周值.结果表明,该分散阈值与ZrO2-Al2O3复合载体中ZrO2的负载量有关,当ZrO2的负载量为0.60 g/g时,NiO的分散阈值达到最高值0.315 g/g.热重-微分热重和程序升温脱附结果表明,NiO在不同ZrO2负载量的复合载体表面形成不同的相互作用和分布状态,复合载体中ZrO2的负载量影响催化剂表面活性中心的种类和对CO2的吸附.同时考察了不同ZrO2负载量的复合载体Ni基催化剂在CO2重整CH4反应中的活性和稳定性.     

纳米Pd上H2O2的电催化还原反应

利用纳米Pd颗粒修饰的Au旋转圆盘电极, 通过强制对流条件下的线性电势扫描伏安法, 研究了酸性介质中H2O2在纳米Pd催化剂上的电还原反应. 动力学研究结果表明, H2O2在纳米Pd上电还原反应的表观活化能为27.6 kJ·mol-1, 反应为2电子转移过程, 电解质的阴离子类型显著影响纳米Pd对H2O2电化学还原反应的催化性能. 根据动力学电流与H2O2浓度及与H+浓度的关系, 提出了Pd催化H2O2电还原反应可能的速率控制步骤, 并讨论了其可能的反应机理.     

Na2[(VO)2(HPO4)2C2O4].2H2O: crystal structure determination from combined powder diffraction and solid-state NMR

The vanadyl oxalatophosphate Na2[(VO)2(HPO4)2C2O4].2H2O has been synthesized by hydrothermal treatment. Its structure has been determined and refined by combining X-ray powder diffraction and solid-state NMR techniques. It crystallizes with monoclinic symmetry in space group P2(1), a = 6.3534(1) A, b = 17.1614(3) A, c = 6.5632(1) A, beta = 106.597(1) degrees . The structure is related to that of (NH4)2[(VO)2(HPO4)2C2O4].5H2O, which was previously reported. The vanadium phosphate framework consists of infinite [(VO)(HPO4)] chains of corner-sharing vanadium octahedra and hydrogenophosphate tetrahedra. The oxalate groups ensure the connection between the chains to form a 2D structure. The sodium ions and the water molecules are located between the anionic [(VO)2(HPO4)2C2O4]2- layers. The thermal decomposition has been studied in situ by temperature-dependent X-ray diffraction and thermogravimetry. It takes place in three stages, where the first two correspond to water removal and the last to the decomposition of the oxalate group and water elimination, leading to the final product NaVOPO4.     

New framework connectivity patterns in templated networks: the creatinine zinc phosphites C4N3OH7.ZnHPO3, C4N3OH7.Zn(H2O)HPO3, and (C4N3OH7)2.ZnHPO3.H2O

The syntheses, crystal structures, and properties of C(4)N(3)OH(7).ZnHPO(3), C(4)N(3)OH(7).Zn(H(2)O)HPO(3), and (C(4)N(3)OH(7))(2).ZnHPO(3).H(2)O are reported. These new creatinine zinc phosphites are built up from networks of vertex-sharing HPO(3) pseudopyramids and various types of ZnO(2)N(2), ZnO(3)N, and ZnO(2)N(H(2)O) tetrahedra, resulting in extended structures of different dimensionalities (as sheets, clusters, and chains, respectively). They demonstrate the structural effect of incorporating "terminal" (nonnetworking) Zn-N and Zn-OH(2) moieties into zinc centers. Crystal data: C(4)N(3)OH(7).ZnHPO(3), triclinic, P1 (No. 2), a = 8.9351(4) A, b = 9.5011(4) A, c = 9.9806(4) A, alpha = 87.451(1) degrees, beta = 85.686(1) degrees, gamma = 89.551(1) degrees, Z = 4; C(4)N(3)OH(7).Zn(H(2)O)HPO(3), monoclinic, P2(1)/c (No. 14), a = 10.1198(7) A, b = 7.2996(5) A, c = 13.7421(9) A, beta = 107.522(1) degrees, Z = 4; (C(4)N(3)OH(7))(2).ZnHPO(3).H(2)O, triclinic, P1 (No. 2), a = 10.7289(6) A, b = 10.9051(6)A, c = 13.9881(8) A, alpha = 89.508(1) degrees, beta = 74.995(1) degrees, gamma = 74.932(1) degrees, Z = 4.     

负载型纳米ZrO2/Al2O3复合载体的制备和表征及其Ni/ZrO2/Al2O3催化性能的研究

以大孔Al2O3为基载体，采用沉积-沉淀法和溶胶-沉积法制备了负载型纳米ZrO2/Al2O3复合载体．用XRD、TEM和比表面与孔径测定等手段对载体进行了表征．结果表明，负载型纳米ZrO2/Al2O3复合载体具有较大的比表面积和适宜的孔径分布，纳米ZrO2在载体上呈单层均匀分布．以CH4-CO2重整制合成气为探针反应，考察了Ni/ZrO2/Al2O3催化剂的活性和选择性．     

Effects of ZrO2 on the Performance of CuO-ZnO-Al2O3/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO2 Hydrogenation

A series of composite catalysts were prepared by the wet mixing method,and the mass ratio of CuO-ZnO-Al_2O_3-ZrO_2 component to HZSM-5 zeolite(molar ratio of SiO_2 to Al_2O_3 being 25)was 2:1. The CuO-ZnO-Al_2O_3-ZrO_2(CuO/ZnO/Al_2O_3=3/6/1 by weight)component was prepared by a modified‘two-step’co-precipitation inethod.The effects of ZrO_2 on the performance of CuO-ZnO-Al_2O_3/HZSM-5 catalyst for dimethyl ether synthesis from CO_2 hydrogenation were investigated.It was found that ZrO_2 improved the properties of CuO-ZnO-Al_2O_3/HZSM-5 as a structural promoter.