镀锡层上钛-磷复合体系钝化膜的制备与表征

通过钛盐与磷酸盐体系复配的方法,在镀锡层表面得到了一种钛-磷复合体系钝化膜. 利用扫描电子显微镜(SEM)、X射线光电子能谱 (XPS)、盐雾试验、Tafel极化曲线和EIS交流阻抗谱测试等方法,研究了所得钝化膜的表面形貌、组成与耐蚀性能. 结果表明,得到的钝化膜层的主要组成成分为Ti₃(PO₄)₄nH₂O和TiO₂,在镀锡层表面结晶细致并有封孔的作用,因此有很好的耐蚀性能.     

具有不同电荷和手性的Co(Ⅲ)配合物跨人红细胞膜的动力学研究

研究了4种不同电荷的Co(Ⅲ)金属配合物跨人红细胞膜的动力学,并测定了它们跨人红细胞膜的一级反应动力学速率常数,发现[Co(C₂O₄)₃]^3-的跨膜速率明显高于[Co(en)₃]³⁺,[Co(en)₂(C₂O₄)]⁺和[Co(en)(C₂O₄)₂]^-,后3种配合物的跨膜速率常数随正电荷的减少略有增加,跨膜机制为简单扩散.[Co(C₂O₄)₃]^3-的跨膜速率受阴离子通道抑制剂DIDS明显抑制,抑制率为51.95%,推测其跨膜机制为部分经阴离子通道协同简单扩散过膜.人红细胞摄入L-[Co(C₂O₄)₃]^3-的速率明显大于D-[Co(C₂O₄)₃]^3-,显示了一定的手性选择性.     

用二维核磁共振研究[Co(phen)2(HNAIP)]Cl3配合物与错配及正常寡聚核苷酸的作用

为了开发能识别正常与错配核酸的探针, 首次合成了[Co(phen)₂(HNAIP)]Cl₃金属配合物, 并利用二维核磁研究了此配合物与错配d(CCGAATGAGG)₂及正常d(CCTAATTAGG)₂寡聚核苷酸的相互作用, 首次发现, [Co(phen)₂(HNAIP)]Cl₃是从“大沟”插入到错配碱基对G₃A₄和G₇A₈之间, 能够很好地识别G:A错配; 而[Co(phen)₂(HNAIP)]Cl₃与正常的寡聚核苷酸的作用, 则是从小沟插入, 即[Co(phen)₂(HNAIP)]Cl₃与错配和正常寡聚核苷酸在不同位置及不同沟槽存在明显的插入式结合、并且有明显的差异, 这就有可能被用来作为识别正常与错配寡聚核苷酸的探针.     

金属有机骨架材料/聚酰亚胺混合基质膜的制备及气体分离性能

合成了3种不同结构、 粒径和气体吸附性能的金属有机骨架材料(MOFs): 微米级Cu₃(BTC)₂、 亚微米级ZIF-8和S-Cu₃(BTC)₂. 氮气吸附等温线分析结果表明, ZIF-8和Cu₃(BTC)₂具有较大比表面积(1653和1439 m²/g), S-Cu₃(BTC)₂的比表面积为171.4 m²/g. 用共混法将MOFs直接引入聚酰亚胺中制备了MOFs/聚酰亚胺混合基质膜(MMMs). X射线衍射(XRD)和全反射红外光谱(FTIR-ATR)分析结果表明, MOFs在混合基质膜中保持物理和化学稳定. 气体渗透测试结果表明, MOFs的加入使膜的气体渗透分离性能明显提高, S-Cu₃(BTC)₂使渗透系数增加了1.75倍; ZIF-8和Cu₃(BTC)₂使渗透系数增加了3倍左右; 同时, 膜的气体分离系数变化很小.     

聚合物模板辅助镍微球的水热制备

以三嵌段共聚物HO(CH₂CH₂O)₂₀(CH₂CH(CH₃)O)₇₀(CH₂CH₂O)₂₀H (P123)为模板剂, 次亚磷酸钠为还原剂, 水热制备了微米级镍微球. 采用X射线衍射(XRD)、扫描电镜(SEM)和振动样品磁强计(VSM)对产物进行表征. 结果表明, 镍微球由纳米级的镍微晶组成, 其中至少部分微球存在空心结构. 微球的尺寸随着前驱体溶液pH值的增加而减小, 其聚集成链的程度随着水热温度的上升而增强. 120和220 ℃水热合成微球的直径范围、平均微晶尺寸和矫顽力分别是1.5～4.5和0.8～4.5 μm, 16.0和14.2 nm, 以及91.5和66.1 Oe.     

富氢气氛下CO选择性氧化催化剂Pt/γ-Al2O3中添加钴的作用

研究了Pt/γ-Al₂O₃催化剂上添加Co对降低Pt负载量的效应,同时通过XRD,CO-TPD,H₂-TPR和FTIR等手段对Co助催的Pt/γ-Al₂O₃催化剂进行了表征,藉此探讨了Co的改性作用.实验结果表明,在Pt/γ-Al₂O₃催化剂中添加Co可显著降低Pt的用量和改善低温活性.在Pt负载量为w_Pt=0.01,Co添加量为w_Co=0.015～0.03时,在ψ_O2/ψ_CO=1.0和120℃的较低温度下,CO转化率和O₂选择性分别高达99%和47%以上.在Pt/γ-Al₂O₃催化剂中添加的Co以不完全还原的CoO_x形态存在,不仅可以提供活泼氧与CO反应生成CO₂,而且影响Pt的电子性能,使之较难还原.Co的引入还削弱了CO在Pt上的吸附,使CO线式吸附物种消失,同时使碳酸氢盐和甲酸盐吸附物种增加.随温度升高,Co/Pt/γ-Al₂O₃催化剂上碳酸氢盐物种消失并转化成CO₂.     

电结晶铜/钴纳米多层膜结构与磁性能研究

以n型Si(111)为基底, 在硼酸镀液体系中采用双槽法电结晶制备Cu/Co纳米多层膜, 确定了工艺条件. 用扫描电镜(SEM)和X射线衍射(XRD)对纳米多层膜的结构和形貌进行了表征, 显示多层膜具有良好周期性和超晶格结构. 并用物性测量系统PPMS测试了不同结构 Cu/Co纳米多层膜的磁性能. 磁滞回线表明: 不同周期数的纳米多层膜其矫顽力均较小. 巨磁阻(GMR)性能与纳米多层膜结构有关. GMR值随Co磁性层厚度增长先增大后减小, 有一极值; 随着Cu非磁性层厚度的增加GMR值发生周期性的振荡; 随周期数N的增大, GMR值先增大, 在N为60时达到了90%, 随着N的继续增加而减小, 当达到80周期时, GMR值趋于稳定.     

顺式二氯二氨合铂与核苷作用的13C核磁共振研究

本文用¹³C NMR法系统研究了溶液中顺式二氯二氨合铂与胸苷、胞苷、鸟苷和5'-腺嘌呤单核苷酸的作用,确定了不同条件下形成配合物的组成及其分子申铂原子与配体的成键方式。在中性介质中顺铂分别与胸苷、胞苷作用,生成N₃配位的顺-[Pt(NH₃)₂(ThyH_-1)₂]和顺-[Pt(NH₃)₂(Cyt)₂]²⁺;与鸟苷随摩尔比不同相应生成顺-[Pt(NH₃)₂(N₂-Guo)₂]²⁺和[Pt(NH₃)₂(N₂,N₁-GuoH_-1)]_nⁿ⁺,当pH=3和摩尔比为1时,尚有微量[Pt(NH₃)₂(N₇,O(C₆)Guo)]²⁺生成;在中性介质中顺铂与5'-AMP亦随摩尔比不同,生成顺-[Pt(NH₃)₂(N₇-5'-AMP)₂]^2-或兼生成顺-[Pt(NH₃)₂(N₇,N₁-5'-AMP)]_n。根据所得结果讨论了顺铂抗癌作用机制,提出了顺铂可能与DNA同一链上相邻二个鸟嘌呤基上的N₇N₁键合形成链内交联的新机制。     

电化学合成系列锡配合物及纳米SnO2的制备

采用锡金属为"牺牲"阳极,首次在无隔膜电解槽中,电化学一步法制备了纳米SnO₂前驱体锡配合物Sn(OEt)₄, Sn(OBu)₄, Sn(OCH₂CH₂OCH₃)₄, Sn(OEt)₂(acac)₂, Sn(OBu)₂(acac)₂, Sn(OCH₂CH₂OCH₃)₂(acac)₂[acac为乙酰丙酮基],产物通过红外光谱(FT-IR)、拉曼光谱和核磁共振进行表征.同时采用含Sn(OR)₂(acac)₂>的电解液直接水解制备纳米SnO₂粉体,纳米SnO₂通过X射线粉末衍射(XRD)和透射电子显微镜(TEM)进行表征.实验表明,电解时防止阳极钝化,控制温度在40～60℃之间,采用有机胺溴化物为导电盐,可以提高电合成效率;电解合成Sn(OCH2CH₂OCH₃)₄, Sn(OEt)₂(acac)₂, Sn(OBu)₂(acac)₂, Sn(OCH₂CH₂OCH₃)₂(acac)₂的电流效率比Sn(OEt)₄, Sn(OBu)₄高,适宜作为溶胶-凝胶(Sol-gel)法制备纳米SnO₂的原料,制备得到的纳米SnO₂经600℃煅烧后呈球形单分散结构,晶型为四方锡石型,平均粒径在(10±0.4) nm左右.     

工况表征方法揭示燃料电池催化层中过氧化氢浓度（英文）

在质子交换膜燃料电池(PEMFC)中,阴极氧还原反应(ORR)所产生的副产物(H₂O₂及其衍生物种)会进攻催化剂,造成性能衰减.该进攻被认为是M/N/C(M=Fe,Co,Ni等)型非贵金属氧还原电催化剂性能衰减的主要原因.因此,M/N/C催化剂的H₂O₂耐受性以及相关的衰减机制值得深入研究.为了准确评估M/N/C催化剂的H2O2耐受性及研究相关衰减机制,前提条件是选取合适的H₂O₂浓度.但是,由于缺乏相应的燃料电池工况表征方法,因而无法得知催化层中H₂O₂的真实浓度.本文发展了一种在燃料电池运行过程中检测催化层中H₂O₂浓度的工况探针方法.采用Pt网作为电化学探针,一面用纤维膜覆盖,另一面贴合质子交换膜,通过热压方法制备膜电极,保证探针位于膜和阴极催化层之间.在燃料电池运行过程中,在Pt探针上施加一个高的氧化电位,氧化转移到探针电极上的H₂O     

硼酸系电结晶制[Co/Pt]_n(n≥40)金属多层膜的研究

于钝铜片及玻碳上采用双电解池恒电位结晶制取了［Ｃｏ（０．５ｎｍ～２．２ｎｍ）／Ｐｔ（２．０ｎｍ）］ｎ（ｎ≥４０）金属多层膜．低角度Ｘ射线衍射表明多层膜有良好的周期性调制结构,其Ｂｒａｇｇ峰的半幅值随着钴层电结晶电位的负移和铂层电结晶电位正移而减小．中角度Ｘ射线衍射表明界面上存在ＣｏＰｔ３金属化合物．多层膜的磁滞回线表明该多层膜的易磁化轴平行于膜面,表现出平面磁各向异性．以低过电位镀Ｃｏ（厚度约０．５ｎｍ）的多层膜的垂直方向磁滞回线形状较好,有望表现出垂直磁各向异性．     

Effects of annealing temperature on magnetic property and structure of amorphous Co49Pt51 alloy nanowire arrays prepared by direct-current electrodeposition

Co49Pt51 nanowire arrays with an average diameter of 35 nm and lengths up to several micrometers were grown in an ordered porous anodic aluminum oxide (AAO) template using direct-current electrodeposition. The as-deposited samples were annealed at 100, 200, 300, 400, 500, 600, and 700 degrees C, respectively. The temperature dependence of the magnetic property of the Co49Pt51 nanowire arrays associated with the microstructure was analyzed by X-ray diffraction and a vibrating sample magnetometer. Magnetic measurements show that the samples both as-prepared and annealed at low temperatures have excellent perpendicular anisotropy. The perpendicular coercivity (Hc(perpendicular)) of Co49Pt51 alloy nanowire arrays increases dramatically as the annealing temperature (T(A)) rises, reaches a maximum(Hc(perpendicular) = 2770 Oe) at 400 degrees C, and then decreases sharply as T(A) rises further. This phenomenon should be attributed to the special structure of the nanowire arrays/AAO, and the microstructure factors significantly change during the annealing process.     

Preparation and Characterization of Pt/Co‐Core Au‐Shell Magnetic Nanoparticles

Pt/Co‐core Au‐shell nanoparticles were synthesized via a two‐step route using NaBH₄ as a reducing agent. The nanoparticles are characterized by UV‐vis spectroscopy, transmission electron microscopy (TEM) and powder X‐ray diffraction (XRD). The results indicate that the as‐synthesized Pt/Co‐core Au‐shell nanoparticles have a disordered face centered cubic (fcc) structure, whereas the annealed Pt/Co‐core Au‐shell nanoparticles exhibit an ordered face centered tetragonal (fct) structure. Superconducting quantum interference device (SQUID) studies reveal that the coercivity of the annealed Pt/Co‐core Au‐shell nanoparticles increases to 510 Oe after heat treatment at 500 °C for 2 h.     

Physical and magnetic modification of co/pt multilayers by ion irradiation.

The microstructure of Co/Pt multilayers with large perpendicular magnetic anisotropy (PMA) was investigated before and after energetic ion irradiation. No pronounced microstructural changes were detected at ion doses sufficient to completely reduce the PMA and cause a spin reorientation transition to in-plane. Ion-induced displacement of Co and Pt atoms near Co/Pt interfaces lead to local "roughening" and Co layer strain relaxation, reducing the PMA. The magnetic domain confinement induced by ion irradiation and magnetic patterning by selective ion irradiation were also investigated.     

电结晶制〔Co/Pt〕_n(n≥50)超晶格的研究

用电结晶法制取了〔Ｃｏ（２．５ｎｍ）／Ｐｔ（２．５ｎｍ）〕ｎ（ｎ＝５０）超晶格．通过控制过电位以控制多层膜的生长．应用了具有高空间实分解能的反射电子显微镜法（ＲＥＭ）直接观察Ｐｔ（Ⅲ）面上的原子台阶以及在Ｐｔ（Ⅲ）上的Ｃｏ的生长方式,发现在高过电位Ｅ＝－１．１５Ｖ（ｖｓ．Ｈｇ／Ｈｇ２ＳＯ４）下Ｃｏ以三维生长方式成膜．用小角度Ｘ射线衍射法证实在Ｐｔ（Ⅲ）面上确实形成了人工超晶格,其周期ｄ＝５ｎｍ．     

Perovskite-like Metal Formates with Weak Ferromagnetism and as Precursors to Amorphous Materials

Three isomorphous compounds M(CHOO)3[NH2(CH3)2] (M = Mn(1 x Mn), Co(2 x Co), Ni(3 x Ni)) have been synthesized in solvothermal conditions. Single-crystal X-ray diffraction shows that they are all crystallized in the trigonal space group R c with small differences in the lattice parameters. Bridged by the three-atom single-bridge CHOO-, M ions form a three-dimensional distorted perovskite-like structure with dimethylamine (DMA) cations located in the cages of the network. Based on the magnetic data, these three 3D compounds are weak ferromagnets with the critical temperature Tc = 8.5 K (1 x Mn), 14.9 K (2 x Co), and 35.6 K (3 x Ni), and for 2 x Co and 3 x Ni, spin reorientation might take place at 13.1 and 14.3 K, respectively. At 1.8 K, hysteresis loops can be observed for all three compounds with the coercivity field ca. 90 Oe (1 x Mn), 920 Oe (2 x Co), and 320 Oe (3 x Ni). The canting angles are estimated to be 0.08 degrees, 0.5 degrees, and 0.6 degrees for 1 x Mn, 2 x Co, and 3.Ni, respectively. The magnetic coupling between MnII ions in 1.Mn was estimated based on the model developed by Rushbrook and Wood for a Heisenberg antiferromagnet on a simple cubic lattice and the best fit gives J = -0.23 cm(-1). At the same time, according to molecular field theory of antiferromagnetism, the J values for compounds 1 x Mn, 2 x Co, and 3 x Ni were estimated to be -0.32 cm(-1), -2.3 cm(-1), and -4.85 cm(-1), respectively. The spin cant in these compounds may originate from the noncentrosymmetric character of the three-atom single-bridge CHOO-. Furthermore, amorphous materials 4 x Mn238, 5 x Mn450, 6 x Co320, and 7 x Ni300 were prepared from precursors 1-3 under an argon atmosphere at different temperatures according to the thermogravimetric analyses. As an interesting result, 5 x Mn450 was confirmed to be an amorphous form of Mn3O4 with a considerably large coercivity field HC = 4.1 kOe at 30 K compared to that value (250 Oe) for bulk Mn3O4.     

Length-controllable catalyzing-synthesis and length-corresponding properties of FeCo/Pt nanorods

Newly designed magnetic-alloy/noble-metal FeCo/Pt nanorods have been first reported and fabricated through a length-controllable catalyzing-synthesis process in which the growth of FeCo nanorods was induced on Pt nanotips. The length of FeCo/Pt nanorods depends on the number of platinum nanotips. The proposed synthesis mechanism was corroborated by scanning electron microscopy, transition electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. With the decrease of Fe content in Fe(x)Co(96-x)/Pt(4) nanoalloys from 77 to 15, the morphology changes from nanorods with different lengths to nanoparticles. The analysis of the magnetic hysteresis loops indicated that the magnetic saturation and coercivity were strongly dependent on the length of the nanorods in which maximum saturation magnetization and minimum coercivity were obtained for Fe(77)Co(19)/Pt(4) nanorods with the length of ～2.5 μm. In particular, FeCo/Pt exhibited length-dependent reactivity towards 1,1,2,2-tetrachloroethane, and Fe(77)Co(19)/Pt(4) nanorods with the length of ～2.5 μm yielded the greatest dechlorination rate. Moreover, Pt can enhance the dechlorination of 1,1,2,2-tetrachloroethane.     

Co3O4 纳米棒的溶剂热合成及形成机理分析

Co3O4 nanorods have been synthesized at 160℃ for 10 h in the solution of oleic and n-cetane by an emulsion-solvothermal method using Co（NO3）2·6H2O as starting materials. The as-prepared product was characterized by X-ray powder diffraction（XRD）,transmission electron microscope（TEM）,and vibrating sample magnetometer（VSM）. The formation mechanism of the prepared product was analyzed based on formation of rod-like micelles of oleic acid. Cobalt ions can migrate into the micelle core for the nucleation and growth of Co3O4 . The results show that the as-prepared Co3O4 nanorods are with the average size 25×100 nm and in the cubic phase. The magnetic susceptibility meets about linearly with the applied magnetic field at room temperature,and the coercivity （Hc）and remanent magnetization（Ms）values of the product at room temperature are 353 Oe and 0.4 emu/g,respectively. This simple route is also expanded to synthesize other materials with the rod-like morphology.     

Catalytic methanation reaction over alumina supported cobalt oxide doped noble metal oxides for the purification of simulated natural gas

A series of alumina supported cobalt oxide based catalysts doped with noble metals such as ruthenium and platinum were prepared by wet impregnation method.The variables studied were difference ratio and calcination temperatures.Pt/Co(10∶90)/Al2O3 catalyst calcined at 700 ℃ was found to be the best catalyst which able to convert 70.10% of CO2 into methane with 47% of CH4 formation at maximum temperature studied of 400 ℃.X-ray diffraction analysis showed that this catalyst possessed the active site Co3O4 in face-centered cubic and PtO2 in the orthorhombic phase with Al2O3 existed in the cubic phase.According to the FESEM micrographs,both fresh and spent Pt/Co(10∶90)/Al2O3 catalysts displayed small particle size with undefined shape.Nitrogen Adsorption analysis showed that 5.50% reduction of the total surface area for the spent Pt/Co(10∶90)/Al2O3 catalyst.Meanwhile,Energy Dispersive X-ray analysis(EDX) indicated that Co and Pt were reduced by 0.74% and 0.14% respectively on the spent Pt/Co(10∶90)/Al2O3catalyst.Characterization using FT-IR and TGA-DTA analysis revealed the existence of residual nitrate and hydroxyl compounds on the Pt/Co(10∶90)/Al2O3 catalyst.     

Inducing growth of FeNi-Pt match-like magnetic nanoheterostructures on Pt nanotips and dechlorination of hydrochloric ether

Newly designed magnetic FeNi-Pt match-like heterostructured nanorods were synthesized by means of induced growth of FeNi nanorods on Pt nanotips. The proposed synthesis mechanism is corroborated by SEM, TEM, XRD and XPS. The magnetic behavior shows that the magnetic saturation and coercivity are strongly dependent on both the shape and the alloy composition. The saturation magnetizations (Ms) and the coercivity (Hc) of nanorods synthesized are larger than those of nanoparticles because of the relatively large anisotropy of nanorods. Maximum saturation magnetization is obtained for Fe(82) Ni(15) -Pt(3) at 226.6 emu g(-1), whereas maximum coercivity is obtained for Fe(20)Ni(77)-Pt(3) at 136.8 Oe. Shape-dependent reactivity toward the reduction of chlorinated solvents was observed for the FeNi-Pt heterostructured nanomaterials. In particular, the Fe(82)Ni(15)-Pt(3) nanorods are highly reactive in the dechlorination process of 1,1,2,2-tetrachloroethane.