Redox Properties of Cobalt Nitrides for NO Dissociation and Reduction

Redox reactions catalyzed by cobalt nitrides should be carried out below the critical temperature at which bulk oxidation of the nitrides occurs. Then, a catalytic redox cycle could be established by introducing a reducing agent into the system below this temperature so that the oxygen could be removed prior to the occurrence of bulk oxidation.     

Bimetallic Cobalt/Rhenium Systems: Preferred Position of Rhenium Through an Interdisciplinary Approach

Some commercial type Fischer–Tropsch catalysts are based on rhenium-doped cobalt. In an attempt to elucidate the preferred position of rhenium in the cobalt matrix, we have carried out experimental Low Energy Ion Scattering investigations of oxidized and reduced catalyst samples and computational DFT investigations of bimetallic Co/Re clusters. The results indicate that rhenium preferentially occupies subsurface sites, where it can coordinate to a maximum number of cobalt atoms.     

铁、钴系烯烃聚合催化剂的研究进展

铁、钴系烯烃聚合催化剂具有易合成、低成本、少污染、高活性以及所制备的聚烯烃（聚乙烯）的相对分子质量分布宽等优点,显示出良好的工业应用前景。综述了铁、钴系单活性中心催化剂的结构特征和铁、钴系催化剂用于不同单体聚合的研究进展,包括铁、钴系催化剂催化乙烯、丙烯、苯乙烯及极性单体的聚合等。     

过渡金属氮化物制备方法及吸氢机理研究进展

介绍了过渡金属氮化物的制备方法,讨论了影响程序升温氮化法的因素;分析了过渡金属氮化物催化剂的吸氢活性、吸附机理.与传统的过渡金属硫化物催化剂相比具有更加优异的氢吸附、活化和转移能力.在加氢脱硫、加氢脱氮和其他涉氢反应中有着广泛的应用.     

原子吸收法测定颜色玻璃中的铁钴铜

用火焰原子吸收法测同时测定颜色玻璃中的着色元素Fe、Co、Cu获得了满意的结果,样品加标回收率95.3%～101.2%,相对标准偏差1.30～1.88,方法简便快速,给颜色转换提供了可靠的数据。     

镍钴铜铁和稀土混合废料中各元素的分离提纯

综合使用溶剂萃取法和化学沉淀法,研究了从镍钴铜铁和稀土混合废料中分离各主要有价金属元素的工艺条件。通过前处理,得到有价金属溶液,调节pH值为2.0沉淀稀土元素,在pH值为1.0时用Acorga M5640萃取分离铜,再在pH值等于5.0时用Cyanex 272萃取钴,剩余水相溶液用来制取镍皂,从而使镍钴铜铁和稀土元素逐步得以分离提纯处理,达到处理含镍钴铜铁和稀土元素的混合废料,回收有用物质,控制污染,保护环境的目的。     

含钴废渣硫酸化焙砂浸出液中钴、铁、锰分离研究

对某锌厂含钴废渣硫酸化焙砂浸出液进行了钴与铁、锰分离工艺研究。研究表明 ,焙砂用水浸出时延长时间为 3.5h,可使大量铁以黄铁矾的形式除去 ,再控制溶液 p H3～ 3.5,温度 1 0 0°C,时间 1 h的条件下 ,采用针铁矿法除铁 ,铁的去除率可达 99.5% ,然后控制溶液 p H4～ 4.5,温度1 0 0°C,用 1 0 % ( NH4 ) 2 S2 O8溶液氧化 Mn2 + 为沉淀而除去 ,锰的去除率为 99.8% ,同时还可氧化Fe2 +达到深度除铁的目的 ,铁的总去除率达 99.9%。在此过程中 ,钴的损失率仅为 2 .5% ,取得了令人满意的结果     

The Reduction of Various Nitrides under Hydrogen: Ni3N, Cu3N, Zn3N2 and Ta3N5

Metal nitrides may be of interest as potential sources of activated nitrogen which can be reacted with target organic molecules. Accordingly, the reduction of nitrogen within Ni₃N, Cu₃N, Zn₃N₂ and Ta₃N₅ under a 1/3 Ar/H₂ flow at elevated temperature has been determined as a simple test of lattice nitrogen reactivity. As anticipated by consideration of their stability, Ni₃N and Cu₃N are reduced completely at 250?°C with up to 30?% of their total lattice nitrogen yielding ammonia. The elimination of N₂ results in the formation of pores which are particularly pronounced in the case of the denitrided Cu system. In the case of Zn₃N₂, the lattice nitrogen is less reactive with incomplete denitridation being observed at 400?°C and the amount of ammonia produced being 15?% of the total nitrogen available. Although Ta₃N₅ contains the least reactive nitrogen of the four samples studied, it can be regenerated by ammonolysis which is an important consideration in any envisaged application.     

玻璃着色元素铁、钴、镍、硒的同时测定

研究了利用电感耦合等离子体原子发射光谱仪同时测定玻璃中着色元素铁、钴、镍、硒的分析谱线、射频发生器功率、雾化气流量等工作参数的选择,建立了ICP-AES法同时测定玻璃中铁、钴、镍、硒的方法,方法的相关系数在0.999以上,RSD值不大于10%,各元素回收率在86.0%至106.7%之间,可满足生产及科研的需要.     

覆碳铁、钴、镍纳米复合材料对AP的催化热分解

通过400℃,500℃、600℃热解含Fe,Co,Ni的高聚物前驱体（M-PAA,M为Co,Fe,Ni）制备覆碳的Fe,Co,Ni纳米复合材料（M／C）,研究了其对AP热分解的影响。XRD和TEM结果表明,500℃热解M-PAA均可获得纳米Fe（Co或Ni）／C材料,热解产物中Co,Fe,Ni颗粒的平均粒径分别为13nm,18nm和20nm。DTA研究结果表明,添加500℃热解所得的M／C（M／C-500）对AP的热分解有明显的催化作用,其催化作用随着M／C-500添加量的增加而增加,Ni／C-500,Fe／C-500,Co／C-500分别使AP高温分解峰最大可降低54．5℃,79．3℃和156．2℃。其中Co／C-500可使AP的高温和低温分解峰发生重叠。     

染发剂中铁、铜、铬、镉、铅、镍和钴等重金属含量测定

建立了微波消解前处理,电感耦合等离子发射光谱(ICP-AES)测定染发剂中铁、铜、铬、镉、铅、镍和钴等重金属含量的方法。该方法各元素检出限均为0.05 mg/kg,线性范围0～500 ng/mL,加标回收率86.8%～108.0%,相对标准偏差为0.98%～5.54%。该方法简便、灵敏,结果稳定准确,可以用于染发剂中重金属含量的测定。     

Separation of Iron,Cobalt, Nickel,and Cadmium in Aqueous Acid Halide Solution Using Aliquat-Foam Columns

Abstract

Polyurethane foam loaded with Aliquat 336 was prepared. The suitability of the prepared reagent foam for the separation of various relative concentrations of iron and cobalt in acidic aqueous solutions was confirmed using the static technique. The separation of other metal couples was achieved on the basis of similar ideas. Columns packed with the Aliquat foam were successfully used in the separation of iron or cadmium from cobalt and nickel. The foam column performance proved quite reasonable, and the application of relatively high flow rates (10 mL/min) was found to be possible.     

Reactions Between Metallic Iron and Cobalt Oxide-Bearing Sodium Disilicate Glass

Electrochemical reactions are initiated at a glass-metal interface if thermodynamic equilibrium, represented by saturation of the glass with the low-valent oxide of the substrate metal, is not present at the interface. On heating the system iron-sodium disilicate glass (with or without cobalt oxide) in platinum crucibles, the metal oxidized with the addition of atmospheric oxygen to the glass. Such weight gains did not occur on heating the system in alumina crucibles. With glasses containing cobalt ions, whose potential for oxidation is lower than that of iron, electrochemical reactions resulted in oxidation of iron at the interface and reduction of metallic ions in the glass with the formation of dendrites. The composition of a precipitating dendrite in all cases was in thermodynamic equilibrium with the adjoining glass. A galvanic cell of iron | glass | glass with cobalt oxide | cobalt illustrated the electrochemical nature of the reactions by oxidation of iron at the iron-glass interface and reduction of cobalt ions at the cobalt-glass interface to form dendrites. In all cases fulfillment of local electroneutrality was largely satisfied by movement of the highly mobile sodium ions, which generally resulted in an uphill composition gradient for sodium because of the establishment of an electrochemical potential gradient.     

Pigments Based on Iron and Cobalt Molybdophosphates for Low-Melting Enamels

The possibility of using pigments based on iron and cobalt molybdophosphates for synthesis of low-melting enamels is demonstrated.     

新型高活性铁、钴催化剂

概述了新型高活性后过渡金属Ｆｅ（Ⅱ）、Ｃｏ（Ⅱ）催化剂的结构、合成及其催化乙烯、丙烯均聚的性能。此类催经剂是以带有大取代基的吡啶二亚胺为主配体的五配位络合物,在甲基铝氧烷等助催化剂的激活下具有极高的活性,而且制备简单,催化丙烯聚合时产物等规指数超过以往的各类催化剂,并介绍了其催化机理。     

Reactivity of Myoglobin Reconstituted with Cobalt Corrole toward Hydrogen Peroxide

The protein matrix of natural metalloenzymes regulates the reactivity of metal complexes to establish unique catalysts. We describe the incorporation of a cobalt complex of corrole (CoCor), a trianionic porphyrinoid metal ligand, into an apo-form of myoglobin to provide a reconstituted protein (rMb(CoCor)). This protein was characterized by UV-vis, EPR, and mass spectroscopic measurements. The reaction of rMb(CoCor) with hydrogen peroxide promotes an irreversible oxidation of the CoCor cofactor, whereas the same reaction in the presence of a phenol derivative yields the cation radical form of CoCor. Detailed kinetic investigations indicate the formation of a transient hydroperoxo complex of rMb(CoCor) which promotes the oxidation of the phenol derivatives. This mechanism is significantly different for native heme-dependent peroxidases, which generate a metal-oxo species as an active intermediate in a reaction with hydrogen peroxide. The present findings of unique reactivity will contribute to further design of artificial metalloenzymes.     

钢丝镀层铁基锌钴扩散机理研究

研究钢丝镀层铁基表面锌钴的扩散机理。结果表明：对于铁基钴-锌镀层钢丝,当扩散温度低于锌的熔点时,锌向钴和铁基体中扩散,在镀层外侧形成钴-锌合金,内侧形成铁-锌合金,一旦钴-锌合金形成后,钴不参与后续扩散;在扩散温度高于锌的熔点时,钴和铁向锌液中扩散,锌与铁优先反应形成铁-锌合金,随着扩散时间的延长,钴扩散到铁-锌合金中,形成Fe（Co）Zn13。对于铁基锌-钴镀层钢丝,当扩散温度低于锌的熔点时,其扩散结果与铁基钴-锌镀层钢丝高于锌的熔点时的扩散结果相同,但最初的扩散过程不同。     

Synthesis, Structure, and Electrochemical Characterization of Nanocrystalline Tantalum and Tungsten Nitrides

Nanocrystalline tantalum and tungsten nitrides were synthesized by a two-step ammonolysis reaction of transition metal chlorides. The first step involves ammonolysis of tantalum and tungsten chlorides at room temperature using anhydrous chloroform as the solvent. A second step consists of heat treatment of these as-prepared powders under anhydrous NH₃ atmosphere leading to the formation of tantalum and tungsten nitride nanocrystallites at relatively low temperature (600°–675°C). The ammonolysis, nitridation, structure, morphology, surface area, density, and electronic conductivity of the nitrides obtained were studied and characterized. The electrochemical responses of these nitrides were also measured by cyclic voltammetry using 1 M KOH electrolyte.     

Study of the Kinetics of Ammonia Synthesis and Decomposition on Iron and Cobalt Catalysts

Activity of cobalt and iron catalysts in ammonia synthesis was determined under a pressure of 10 MPa and at the temperature range of 673–823 K, in a six-channel integral steel reactor. The catalytic ammonia decomposition was studied in a differential reactor under the atmosphere of low concentration of ammonia (<6%) in the temperature range of 673–823 K under atmospheric pressure. The determined values of the activation energy for the ammonia synthesis reaction over cobalt and iron catalysts are 268 and 180 kJ/mol, respectively, whilst for the ammonia decomposition reaction they are equal to 111 and 138 kJ/mol. The cobalt catalyst showed lower activity than a commercial iron catalyst in ammonia synthesis reaction. The cobalt catalyst turned out to be more effective in ammonia decomposition reaction than the iron one.