Effects of the Different Supports on the Activity and Selectivity of Iron-Cobalt Bimetallic Catalyst for Fischer-Tropsch Synthesis

Silica, alumina, and activated carbon supported iron-cobalt catalysts were prepared by incipient wetness impregnation. These catalysts have been characterized by BET, X-ray diffraction （XRD）, and temperature-programmed reduction （TPR）. Activity and selectivity of iron-cobalt supported on different carriers for CO hydrogenation were studied under the conditions of 1.5 MPa, 493 K, 630 h^-1, and H2/CO ratio of 1.6. The results indicate that the activity, C4 olefin/（C4 olefin＋C4 paraffin） ratio, and C5 olefin/（C5 olefin＋C5 paraffin） decrease in the order of Fe-Co/SiO2, Fe-Co/AC1, Fe-Co/Al2O3 and Fe- Co/AC2. The activity of Fe-Co/SiO2 reached a maximum. The results of TPR show that the Fe-Co/SiO2 catalyst is to some extent different. XRD patterns show that the Fe-Co/SiO2 catalyst differs significantly from the others; it has two diffraction peaks. The active spinel phase is correlated with the supports.

Simple, Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel(Ⅱ), Copper (Ⅱ), Cobalt (Ⅱ), and Iron (Ⅲ) with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.

Recent advances in cobalt-, nickel-, and iron-based chalcogen compounds as counter electrodes in dye-sensitized solar cells

The electroactive materials used in the counter electrode(CE)are of great concern as they influence the photovoltaic performances of dye-sensitized solar cells.The main functions of CE materials are collecting electrons from the external circuit and transferring them to the electrolyte and realizing the catalytic reduction of the redox species(I3^– or Co^3+)present in the electrolyte.The research hotspot of CE materials is seeking functional materials that display high efficiency,low cost,and good electrochemical stability and can substitute the benchmark platinum electrode.Chalcogen compounds of cobalt,nickel,and iron have been widely applied as CE materials and exhibit excellent electrocatalytic performances owing to their unique electrical properties,similar energies of adsorption of I atoms as platinum,excellent catalytic activities,and good chemical stabilities.In this review,we trace the developments and performances of chalcogen compounds of iron,cobalt,and nickel as CE materials and present the latest research directions for improving the electrocatalytic performances.We then highlight the optimization strategies for further improving their performances,such as fabrication of architectures,regulation of the components,synthesis of composites containing carbon materials,and elemental doping.

Efficient electrocatalytic overall water splitting and structural evolution of cobalt iron selenide by one-step electrodeposition

Developing bifunctional electrocatalysts with both high catalytic activity and high stability is crucial for efficient water splitting in alkaline media.Herein,a Fe-incorporated dual-metal selenide on nickel foam(Co_(0.9)Fe_(0.1)-Se/NF) is synthesized via a facile one-step electrodeposition method.As-synthesized materials could serve as self-supported bifunctional electrocatalysts with excellent catalytic activity towards oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in alkaline media.Experimental results show that delivering a 10 mA cm^(-2) water splitting current density only requires a cell voltage of 1.55 V.In addition,a very stable performance could be kept for about 36 hours,indicating their excellent working stability.Moreover,by means of phase analysis,we have identified that the evolution of the synthesized Co_(0.9)Fe_(0.1)-Se/NF experiences two entirely different processes in HER and OER,which hydroxide and oxyhydroxide are regarded as the real active sites,respectively.This work may pave the way to further understanding the relationships between the reactivity and stability of chalcogenide-based electrocatalysts and facilitating the rational design of efficient electrocatalysts for future renewable energy system applications.

Newly Discovered Native Gold and Bismuth in the Cihai Iron-Cobalt Deposit, Eastern Tianshan, Northwest China

The Cihai iron-cobalt deposit is located in the southern part of the eastern Tianshan iron- polymetallic metallogenic belt. Anomalous native gold and bismuth have been newly identified in Cinan mining section of the Cihai deposit. Ore formation in the deposit can be divided into three stages based on geological and petrographical observations： （I） skarn, with the main mineral assemblage being garnet-pyroxene-magnetite; （II） retrograde alteration, forming the main iron ores and including massive magnetite, native gold, native bismuth, and cobalt-bearing minerals, with the main mineral assemblage being ilvaite-magnetite-native gold-native bismuth; and （III） quartz-calcite- sulfide assemblage that contains quartz, calcite, pyrrhotite, cobaltite, and safflorite. Native gold mainly coexists with native bismuth, and they are paragenetically related. The temperature of initial skarn formation was higher than 340~C, and then subsequently decreased to -312~C and ~266~C. The temperature of the hydrothermal fluid during the iron ore depositional event was higher than the melting point of native bismuth （271~C）, and native bismuth melt scavenged gold in the hydrothermal fluid, forming a Bi-Au melt. As the temperature decreased, the Bi-Au melt was decomposed into native gold and native bismuth. The native gold and native bismuth identified during this study can provide a scientific basis for prospecting and exploration for both gold- and bismuth-bearing deposits in the Cihai mining area. The gold mineralization in Cihai is a part of the Early Permian Cu-Ni-Au-Fe polymetallic ore-forming event, and its discovery has implications for the resource potential of other iron skarn deposits in the eastern Tianshan.

Model of In Situ Composite of Cobalt(Ⅱ)-Phthalocyanine and Carbonyl Iron for Organic/Inorganic Nanocomposites

Cobalt-phthalocyanine/iron nanocomposite particles have been obtained using method of composite in situ, with the mixture of carbonyl iron and solution of cobalt ( Ⅱ ) - phthalocyanine (Co-Pc) ultrasonic dispersing in N,N-dimethyl-formamide (DMF). Structure characterization of their inner and surface have relation with method of carbonyl iron joined in the mixture, contents of carbonyl iron and Co-Pc in the mixture of Co-Pc ultrasonic dispersing in DMF. With a method of composite in situ controlling reasonable experiment condition, it can be obtained that cobalt-phthalocyanine/iron nanocomposite particles has completely been covered with Co-Pc, they had structure of Chinese gooseberry in inner and mere made up of almost regular spherical shape and the average diameter is 1. 4 μm.

PROSPECTS AND CRUCIAL PROBLEMS IN OLIGOMERIZATION AND POLYMERIZATION WITH IRON AND COBALT COMPLEX CATALYSTS

The discovery of highly active 2,6-bis（imino）pyridyl iron and cobalt complexes provided a milestone of latetransition metal catalysts for ethylene oligomerization and polymerization with being currently investigated for the scale-up process. The crucial problems are remaining in the catalytic systems： the catalytic systems targeting ethylene polymerization produce more oligomers at elevated reaction temperatures, however, there is a recognizable amount of high-molecularweight polyethylene remained in the modified catalytic system for the oligomerization process. Beyond the modification of bis（imino）pyridyl metal complexes, several alternative proeatalysts＇ models have been developed in our group. This review highlighted the achievements in exploring new iron and cobalt complexes with tridentate NNN ligands as procatalysts for ethylene oligomerization and polymerization.

CHARACTERIZATION OF COBALT(Ⅱ)-PHTHALOCYANINE-METAL IRON COMPOSITES FOR MAGNETORHEOLOGICAL FLUIDS

Magnetorheological suspension based on 20 (v/V) % CoPc-iron composite particles dispersed in sili-cone oil have been obtained, which exhibited dynamic shear stress up to 2000Pa upon application of external magnetic field at 1300 Oe. The response is faster than 0. 15 -with superior reversibility of changes in viscosity induced by external magnetic field at above 12. 5℃. Further, it was found that the MR fluid is in possession of long-term stability a-gainst sedimentation.

Electrodeposited Cobalt-Iron Alloy Thin-Film for Potentiometric Hydrogen Phosphate-Ion Sensor

A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.

Catalytic Effect of Cobalt and Iron Complexes Incorporating Bis(2-aldiminoethyl)amine Ligands on Ethylene Oligomerization

Complexes [MCl 2{CH 3N(CH 2CH 2N[CDS1]CR 1R 2) 2}]((3, M=Co, R 1=H, R 2=Ph ; 4, M=Fe, R 1=H, \{R 2=Ph\}; 5, M=Co, R 1=R 2=Ph) were prepared and characterized by IR spectra and elemental analysis. The combination of each of complexes 3-5 with ethylaluminoxane(EAO), respectively, was found to be moderately active for ethylene oligomerization to low carbon olefins. The activity of 113 kg oligomers·mol -1 Co·h -1 for complex 3(100 mol of EAO, 180 ℃ and 1 8 MPa ethylene) was observed with a selectivity of 93% to C 4-10 olefins, of which 96% were linear C4 10 olefins. The catalytic properties of complexes 3-5 were compared with those of analogous P,P coordinated complexes [MCl 2{CH 3N(CH 2CH 2PPh 2) 2}](1, M=Co; 2, \{M=\}Fe).

山西中条山宋家山钴铁矿床钴的赋存状态及成矿规律

宋家山钴铁矿床位于中条山地区东南缘“同善天窗”的中部,容矿岩石主要为古元古代宋家山群绛道沟组火山-沉积岩系。钴铁矿体受地层岩性控制,呈SN向层状展布。金属矿物主要为磁铁矿、黄铁矿、黄铜矿、硫铜钴矿和硫钴矿,非金属矿物主要为石英、方解石、绢云母和绿泥石。矿石构造以块状、似条带状、浸染状、团块状和细脉状为主。黄铁矿和黄铜矿多呈浸染状和细脉状分布。围岩蚀变主要包括硅化、绢云母化、黄铁矿化、碳酸盐化和绿泥石化等。钴铁矿体的形成主要包括沉积、变质和热液三个期次。矿石显微镜观察、硫化物扫描电镜和电子探针分析,表明钴元素主要赋存在硫铜钴矿、硫钴矿和黄铁矿中。黄铁矿特征元素Co/Ni比值主要集中在100~1000之间,个别比值小于100,反映硫化物的形成主体与热液活动有关。硫化物原位硫同位素组成δ^(34) S在12‰~16‰之间,低于元古代海水硫酸盐的δ^(34) S值(15‰~20‰),揭示热化学还原(TSR)在海水硫酸盐还原过程中起到关键作用。综合研究表明宋家山矿床富钴矿体的形成经历了初始火山-沉积、造山期间含钴变质流体沿片理构造充填交代、造山后期热液活动的叠加等过程。由此认为宋家山矿床成因类型属沉积-变质热液叠加型钴铁矿床。

镍电解除铜后液氯气氧化沉淀法除铁钴

以氯气(Cl_(2))为Fe^(2+)和Co^(2+)氧化的氧化剂、Na_(2)CO_(3)为沉淀剂,对镍电解阳极液—硫化氢除铜后液深度除铁钴、Cl_(2)利用率和除铁钴渣成分进行了系统研究,用正交试验和单因素条件试验确立了最佳的Cl_(2)氧化沉淀法除铁钴的最佳工艺条件,阐明了除铁钴渣中镍、铁、钴的存在形态。结果表明:Cl_(2)氧化沉淀铁、镍和钴的反应均属于放热反应,能够自发进行,且热力学反应优先顺序为Fe^(2+)>Co^(2+)>Ni^(2+);正交试验和单因素条件试验结果一致,最佳的除铁钴工艺条件为:通Cl_(2)前pH=5.0、通Cl_(2)终点ORP=1050 mV、反应终点pH≥4.5。在此条件下,Fe^(2+)和Co^(2+)去除率分别为99.8%和97%,Cl_(2)利用率大于97%,除铁钴渣的Ni(Fe+Co)=0.88。除铁钴渣主要由Ni、Fe、Co、O、S等元素组成;Ni以+2价为主,Fe和Co则以+3价为主。

磁性ZnO/CoFe_(2)O_(4)复合材料的制备及其光催化性能

为了解决纳米光催化材料在使用后难以回收的问题,采用低温煅烧法制备了磁性ZnO/CoFe_(2)O_(4)复合材料。通过扫描电镜、X射线衍射、红外及紫外-可见漫反射等方法对材料进行了表征,并探讨了ZnO和CoFe_(2)O_(4)不同复合比对材料光催化活性的影响。结果表明,当ZnO与CoFe_(2)O_(4)复合质量比为12∶1时,所得材料的光催化活性最好;在500W氙灯照射下,其对甲基橙的光催化降解活性优于商业P25。光催化捕获实验表明,·OH是降解过程中的最主要活性物种,在重复使用5次后仍有较高的光催化活性,且易于在外部磁场作用下分离回收。

河北某邯邢式铁矿矿石特征及钴的赋存状态研究

采用化学分析、光学显微镜、X射线衍射分析、电子探针以及矿物自动分析系统(AMICS)等手段对矿石进行全面研究,重点关注其化学组成、矿物组成、嵌布特征、矿物粒度以及有用元素钴的赋存状态等工艺矿物学特征。研究结果表明,该矿石中磁性铁的含量占比达到94.23%,主要以磁铁矿为主要回收矿物。而钴的品位为0.014%,硫的品位为1.89%,在回收利用铁资源的同时,可进一步回收硫钴元素。矿石中的主要金属矿物包括磁铁矿、黄铁矿以及少量的铜矿物,非金属矿物主要包括蛇纹石、金云母和碳酸盐矿物等。矿石的结构形式主要为半自形-它形晶粒状结构、交代结构以及包含结构等;构造以块状构造和浸染状构造为主。当矿石破碎至-2mm时,磁铁矿和黄铁矿的粒度较粗。在矿石中并未发现钴的独立矿物存在,钴是以类质同象的形式赋存于磁铁矿、黄铁矿以及褐铁矿中。通过采用适当的选矿工艺,可以获得硫钴精矿,从而进一步富集和回收钴元素。这些研究结果为该矿的综合利用提供了重要的参考和依据。

基于L型铁钴的三维力触觉传感器设计及输出特性

该文提出了一种基于L型铁钴丝的三维力触觉传感器,利用磁致伸缩材料铁钴合金设计制作了三维力触觉传感单元,并测试了该结构的输出特性。基于电磁原理、逆磁致伸缩效应和欧拉伯努利动力学原理,推导了输出电压方程。搭建触觉传感单元实验平台,对传感器进行法向和切向标定,设计的传感器法向测力范围为0~13 N,切向测力范围为0~6 N,输出特性具有良好的线性关系。其中,0~8 N法向力范围内灵敏度约为23.997 mV/N,9~13 N法向力范围内灵敏度约为17.537 mV/N;0~4 N切向力范围内灵敏度约为11.599 mV/N,5~6 N切向力范围内灵敏度约为6.281mV/N。在4Hz频率、2N法向力条件下,该传感器动态响应的输出电压幅值变化范围为46.5~49.8mV,与静态力输出电压幅值的相对误差低于5%,响应时间和恢复时间分别为25 ms和29ms,表明该传感器具有良好的动态特性。分别采用广义逆矩阵和BP神经网络对传感器测得的三维力进行解耦,其中,BP神经网络解耦方法平均误差仅有2.90%,可有效提高测量精度。该传感器体积小、输出线性度好,可同时实现静态力和动态力的测量,在智能机器人等领域具有良好的应用前景。

铁钴共掺杂氮化碳活化过硫酸盐降解双酚A

由于非自由基主导的氧化过程具有高选择性和抗干扰的特点,所以目前对活化过硫酸盐反应的研究主要集中在通过调控配位环境实现非自由基反应的高选择性上。文章以g-C3N4为载体,通过煅烧的方式制备了一种铁钴共掺杂催化剂,并通过引入Co3+/Co2+和Fe3+/Fe2+实现了对双酚A的高效降解。

铁、钴配合物催化烯烃硅氢化反应研究进展

烯烃的硅氢化反应是有机硅化合物的重要合成反应.铂等贵金属配合物常被用于催化烯烃的硅氢化反应,但自然丰度较低、价格高昂,限制了其应用和发展.因此,开发廉价过渡金属配合物催化剂是非常有必要的.以铁、钴为代表的廉价金属配合物催化剂具有成本低、地壳含量丰富、绿色环保等优势,在烯烃的硅氢化反应中表现出较高的催化活性.综述了近年来铁、钴配合物催化烯烃硅氢化反应的研究进展,并展望了该领域存在的机遇和挑战.

活性氧化镁选择性沉淀钴试验研究

针对以刚果(金)铜钴多金属共生矿石为原料的提钴工艺,研究了采用活性氧化镁选择沉淀模拟含钴溶液中的钴并制备粗氢氧化钴,探讨了溶液中氢氧化物沉淀的动力学,考察了氧化镁粒径、氧化镁添加量及添加方式、反应时间、温度对铁、钴、锰沉淀的影响。结果表明:通过添加30%过氧化氢能快速去除模拟含钴溶液中的杂质铁;按照添加量0.68/1、多次加入方式向模拟含钴溶液中添加粒径小于45μm活性氧化镁,在常温下反应6 h所得一级沉淀符合行业标准一级品要求,次级沉淀符合三级品要求。该工艺具有成本低、实用性强等优点,可有效提高氧化镁沉钴效率。

钴铁层状双金属负载生物炭对水体硝氮的吸附研究

水体中的硝氮质量浓度不断升高,对水生态系统和人类健康存在潜在威胁。因此,解决水体中过量硝氮的问题刻不容缓。以Fe(NO_(3))_(3)·9H_(2)O、Co(NO_(3))_(2)·6H_(2)O、芦苇生物炭、NH_(3)·H_(2)O为原料,采用共沉淀法将钴铁层状双金属负载到芦苇生物炭上,制备了可用于吸附水体中过量硝氮的Co/Fe-LDH@BC。结果表明,Co/FeLDH@BC可有效吸附水体中的硝氮,其吸附量为88.52 mg/g;吸附动力学模型符合伪二级动力学模型,等温线符合Langmuir等温线模型,说明吸附反应为自发的、吸热的,主要涉及离子交换、配体交换、静电吸引、氢键四种反应机理;Co/Fe-LDH@BC在大多数共存阴离子的水体中对硝氮具有很强的亲和力,具有实际应用价值。

山东莱芜垂阳矽卡岩型铁矿尾矿中关键金属钴综合利用评价探讨

1研究目的钴是高温合金、电池材料、防腐材料、磁性材料等重要原料,广泛应用于航空航天、电子电器、机械制造、汽车、化工农业、陶瓷等领域,在国民经济和社会发展中具有特殊的意义。特别是从移动电子设备,到新能源汽车的动力电池,再到电网储能,钴作为锂电池正极材料——钴酸锂的重要组成,都是不可或缺。因此,钴被世界上众多国家列为21世纪重要的关键战略资源(Gulley et al.,2018)。现今我国是世界上最大的钴资源进口国(95%依靠进口)和消费国(US Geological Survey,2018),而且钴资源紧缺,保障程度低(蒋少涌等,2019;许德如等,2019)。