Cu-Fe Catalysts Modified by Rare Earths for Preparation of High Alcohols from Fatty Acid Esters Reduction

In order to increase activity of Cu Fe catalyst and use the mixture of nitrogen and hydrogen directly for preparation of high alcohols by reducing fatty acid esters, rare earths were used to modify the catalyst. Experiments show that yield of high alcohols increases by 3% as 1% Sm 2O 3 is added to the catalyst when the reduction is carried out under pure hydrogen. The yield greatly decreases when the reduction is carried out under the mixture of hydrogen and nitrogen. Catalysts activities modified by Y and Nd can be evidently improved and even enhanced. The yields increase by 33% and 29% when 1% Y 2O 3 and 1% Nd 2O 3 are added to the catalyst, respectively.

Cu-Fe合金凝固过程中结构变化研究

采用分子动力学模拟方法研究了Cu_(100-X)Fe_(X)(X=1%、3%、5%)合金在冷却速率为2×10^(10)K/s条件下合金凝固过程.研究表明,Fe含量为1%时,随着合金温度的降低Fe原子始终保持均匀分布的状态,未出现Fe原子聚集现象,晶体结构是以FCC为主的Cu基体,Fe原子以固溶形式存在于基体中.Fe含量为3%时,随着合金温度的降低Fe原子有聚集趋势,但BCC晶体结构占比较小,晶体结构仍是以FCC为主的Cu基体.Fe含量为5%,随着合金温度的降低Fe原子发生明显聚集,最终形成以FCC、HCP晶体类型为主镶嵌Fe原子的Cu基体.研究了Fe团簇的形成过程,结果表明,Fe团簇的形成、长大是一个连续的过程,该过程受形核生长机制控制,不同阶段形成Fe团簇的大小和数量受Fe-Fe原子相互作用力、Fe原子的扩散能力以及Fe团簇与Cu基体间的界面能三个因素共同影响.

高性能Cu-Fe合金薄带材及其短流程制备技术

为了解决Cu-Fe合金常规制备流程中重力分层的问题,利用铸轧工艺的亚快速凝固特点抑制其液相分离,并结合Marangoni效应及热泳力的耦合作用合理调控铸轧参数,获得厚度为2.2~2.4 mm、铁磁相尺寸和分布可控的Cu-20%Fe和Cu-30%Fe带材。通过金相与EBSD分析确定铸带形成了Cu相-富Fe相-Cu相的“三明治”层状复合结构,其中Cu-20%Fe铸带中的Fe相分布更为均匀,且EBSD分析结果表明凝固层中形成了大量的低能晶界,如Σ1和Σ3等。将Cu-20%Fe合金从2.4 mm冷轧至0.4 mm,在不同温度下进行热处理后继续冷轧至0.12 mm。结果表明:450℃热处理对轧板性能更好,导电率超过50%IACS,抗拉强度超过600 MPa,均匀伸长率达到7.5%,饱和磁化强度超过4.24×10^(5)A/m。

Conversion of syngas to higher alcohols over Cu-Fe-Zr catalysts induced by ethanol

Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method, it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol, the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.

Synergistic effects of bimetallic Cu-Fe/SiO_2 nanocatalysts in selective hydrogenation of diethyl malonate to 1,3-propanediol

Cu-x-Fe-y/SiO2 catalysts were prepared using urea-assisted sol-gel method. The structure and physicochemical properties of the catalysts were characterized using N-2 adsorption-desorption, transmission electron microscopy, H-2-temperature-programmed reduction, powder X-ray diffraction, and X-ray photoelectron spectroscopy. Compared with monometallic Cu or Fe catalysts, the bimetallic Cu-x-Fe-y/SiO2 catalysts exhibited enhanced catalytic performance for the selective hydrogenation of diethyl malonate to 1,3-propanediol. The bimetallic catalyst with an optimal Cu/Fe atomic ratio of 2 exhibited the highest activity, which yielded 96.3% conversion to diethyl malonate and 93.3% selectivity to 1,3-propanediol under the optimal reaction conditions. Characterization results revealed that interactions between Cu and Fe contributed to the improvement of diethyl malonate conversion and selectivity to 1,3-propanediol. The X-ray photoelectron spectroscopy results revealed that the addition of appropriate amount of Fe species enhanced the reduction of Cu2+ species, thereby increasing the Cu-0 species on the surface of bimetallic catalyst. It led to a better chemisorption capacity of hydrogen and further promoted of the activation of hydrogen molecule. The ethyl acetate temperature-programmed desorption results indicated that the FeOx species provided the additional adsorption sites for substrate molecules, and they activated the C=O bond. The improved catalytic performance of bimetallic Cu-x-Fe-y/SiO2 catalyst was mainly attributed to the synergistic effect between Cu-0 and FeOx species. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

人工时效处理对体育器材焊接用Al-6Si-2Cu-Fe合金组织与性能的影响

Al-Si-Cu铝合金广泛应用于体育器材中取代铁制零件,该合金的力学特性是其应用中重要的参考依据,其中Al-6Si-2Cu-Fe作为代表合金之一,不同的热处理状态会显著影响合金的显微组织与力学性能,为此,文中研究了不同人工时效处理方式对Al-6Si-2Cu-Fe合金的影响。按先后顺序对合金进行了3种不同的时效处理,分别是预时效、单级时效和双级时效。通过硬度测试、拉伸测试、冲击试验、金相观察和扫描电子显微镜能谱分析进行表征。结果表明,由于时效处理的不同,相组成和形态微结构存在差异,每种处理的差异可以在析出相的显微组织形态中观察到,各析出相包括弥散的、圆形和针状等形态,这些相结构显著影响了合金的力学性能。测试结果显示,单级时效处理获得了最高的硬度和抗拉强度,其分别为160.16 HB和201.45 MPa;预时效处理的冲击韧性最高,其吸收能量为18.55 J。

Treatment of Phenol Wastewater with Cu-Fe/AC Catalyst by Continuous CWPO

The Cu-Fe/AC catalyst was prepared by microwave-assisted synthesis, and its morphological characteristics were characterized. The degradation effect of phenol wastewater by catalytic wet peroxide oxidation(CWPO) was studied, and the response surface methodology(RSM) was used to analyze the influencing factors of the removal rate of COD. The experimental results showed that under the conditions of reaction temperature 80 ℃, reaction time 90 min, initial pH 3.1 and H_(2)O_(2)addition 2.2 g/L, the removal rate of COD reached 82%. The results of response surface methodology indicated that under the conditions of reaction temperature 100 ℃, reaction time 64 min, initial pH 3.3 and H_(2)O_(2)addition 2.7 g/L, the removal rate of COD was up to 86%. After Cu-Fe/AC catalyst was reused for 4 times, the removal rate of COD was still above 80%, revealing that the catalyst showed good catalytic performance.

Bimetallic Single‑Atom Catalysts for Water Splitting

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

Preparation of Co/S co-doped carbon catalysts for excellent methylene blue degradation

S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.

Ce添加对Cu-Fe/SiO_2催化合成气制低碳醇性能的影响

采用共浸渍法制备了添加不同Ce含量(相对于SiO_2的摩尔分数为0-20%)的Ce-Cu-Fe/SiO_2催化剂,在连续流动微型固定床反应器中考察了其催化CO加氢合成低碳醇反应的性能,并采用X射线衍射(XRD)、低温N_2吸附、程序升温还原(H_2-TPR)、CO吸附傅里叶变换红外光谱(CO-FTIR)和CO程序升温脱附(CO-TPD)技术对催化剂进行了表征.结果表吸:添加适量的Ce,一方面降低了Cu的晶粒大小,提高了Cu的分散度,进而提高了对CO的吸附能力;另一方面掺入的Ce和Cu之间存在相互作用,提高了CO解离和非解离吸附的能力,从而有利于CH_x的生成和CO的插入反应.上述两方面的共同作用同时提高了Cu-Fe/SiO_3催化剂的活性和醇的选择性.当Ce含量为10%时,在压力为3.0 MPa,温度为250℃,空速为6000 mL·g^(-1)·h^(-1)和H_2/CO摩尔比为2的反应条件下,Ce-Cu-Fe/SiO_2催化剂上醇的时空产率达到121.0 g·kg^(-1)·h^(-1),比未添加Ce的Cu-Fe/SiO_2催化剂的时空产率(58.0 g·kg^(-1)·h^(-1))提高了一倍以上.

不同载体对负载型Cu-Fe催化剂CO加氢反应性能的影响

以不同的氧化物为载体,采用共浸渍法制备了一系列负载型的Cu-Fe催化剂Cu-Fe/MOx(MOx=ZnO、ZrO2、TiO2、SiO2、MgO、Al2O3),并采用X射线衍射(XRD)、N2吸附(N2-adsorption)、程序升温还原(H2-TPR)和一氧化碳程序升温脱附(CO-TPD)技术对催化剂进行了表征。在温度为250℃、压力为3 MPa和原料气空速为6 000 mL/(g.h)的反应条件下,在连续流动微型固定床反应装置上考察了其催化CO加氢合成低碳醇的反应性能。结果表明,与其他氧化物为载体的催化剂相比,Cu-Fe/SiO2催化剂表面CuO的分散度较高,在较低的温度下容易被还原,具有较强的CO吸附能力,从而同时具有较高的活性和低碳醇选择性。

Cu-Fe基双孔载体催化剂结构和低碳醇合成反应性能

采用超声浸渍法制备了Cu、Fe双活性组元改性的双孔载体(M)催化剂, 采用N2物理吸附、H2程序升温还原/脱附(H2-TPR/TPD)、X 射线衍射(XRD)等表征手段考察了催化剂中Cu-Fe的相互作用, 并在固定床反应器中评价了Cu/Fe摩尔比的改变对低碳醇合成反应性能的影响. 结果表明: 小孔硅溶胶浸渍在大孔硅凝胶中可形成具有不同纳米孔径结构的双孔载体, 增加小孔硅溶胶的含量可促使双孔载体中小孔纳米结构尺寸变小. Fe/Cu摩尔比的增加有利于铜物种在载体表面的分散, 促进了表层CuO和Fe2O3的还原, 加强了双孔载体内孔道与铜铁氧化物之间的相互作用, 促使了单质铜的分散和铁碳化物的生成. CO加氢反应活性和低碳醇时空收率随着Fe/Cu摩尔比的逐渐增加呈现增加的变化趋势. 当Fe/Cu摩尔比增加到30/20时,Cu-Fe基双孔载体催化剂的CO转化率增加到46%, 低碳醇的时空收率增加到0.21 g·mL-1·h-1, C2+OH/CH3OH 质量比达到 1.96.

碱金属对CO加氢制备低碳醇Cu-Fe-Co基催化剂的影响

考察了碱金属(Li、Na、K、Cs)对CO加氢制备低碳醇Cu-Fe-Co基催化剂反应性能的影响。研究发现:碱金属的添加能明显降低甲烷化反应,提高催化剂活性,使醇分布向碳链增长方向转移;碱金属Na的添加对催化剂活性的提高影响最大,与未添加碱金属的催化剂相比,液体产物中总醇质量分数提高45.98%,其中C2+醇和C5+醇在总醇中的摩尔分数分别提高了21.88%和22.89%,尾气中CH4摩尔分数下降42.83%。XRD结果表明,碱金属的加入使Cu、Fe、Co三种组分在载体上分散性加强,增加了CO与活性组分的接触位点从而使碳链增长;FE-SEM结果表明,碱金属Na的添加提高了催化剂孔隙结构和活性组分的均匀性和稳定性,同时减轻了催化剂积炭现象,提高了醇收率。

Cu-Fe合成低碳醇催化剂性能研究

采用共沉淀法制备了Cu-Fe催化剂,用XRD、XPS、TPR和BET等研究了老化时间对催化剂前驱体和催化剂性能的影响。采用固定床加压微反装置,在5.0 MPa、250℃和空速5 000 h-1条件下评价催化剂合成低碳醇的催化活性。XRD研究表明,老化时间对催化剂前驱体的组成和结构以及催化剂中CuO和Fe2O3的分散度有影响;XPS和TPR研究表明,催化剂中CuO和Fe2O3间存在相互作用,强度随老化时间的延长而改变。催化活性受催化剂比表面积和Cu-Fe间相互作用强度的影响;选择性主要受Cu-Fe间相互作用强度影响。高级醇C3+OH的选择性随着老化时间的延长而增大,总醇中C2+OH选择性大于75%。

Cu-Fe系催化剂的比表面、物相和还原行为与活性的关系

对由脂肪酸甲酯加氢制备高碳醇的Ｃｕ－Ｆｅ系催化剂进行了Ｂ．Ｅ．Ｔ．比表面测定，ＸＲＤ，ＴＧ－ＤＴＡ－ＤＴＧ和Ｍｏ¨ｓｓｂａｕｅｒ谱学及与活性数据关联的研究．Ｂ．Ｅ．Ｔ．比表面与焙烧温度及活性的关系研究指出，在４８０℃下焙烧的催化剂，比表面适中，活性最高．ＸＲＤ、ＴＧ－ＤＴＡ－ＤＴＧ及Ｍｏ¨ｓｓｂａｕｅｒ谱学研究指出，催化剂氧化态物相为ＣｕＯ，γ－Ｆｅ２Ｏ３和ＭｇＯ；在反应条件下，ＣｕＯ首先被还原为金属态的铜（Ｃｕ０），接着，γ－Ｆｅ２Ｏ３被还原为Ｆｅ３Ｏ４．催化剂中Ｆｅ组分以γ－Ｆｅ２Ｏ３物相存在，在反应条件下还原为Ｆｅ３Ｏ４，有利于提高催化剂的活性．催化剂的活性与其还原行为密切相关。

Fe、Co组成对Cu-Fe-Co基混合醇催化剂合成性能的影响

采用共浸渍法制备了一系列不同Fe、Co组成的Cu-Fe-Co基混合醇催化剂,对其CO加氢合成混合醇反应性能进行了考察,并采用BET比表面积分析、X射线衍射(XRD)、X射线光电子能谱(XPS)、场发射扫描电子显微镜(FE-SEM)及H_2程序升温还原(H_2-TPR)等手段对其进行了表征.结果表明:Cu-Fe二元催化剂添加适量的Co可以明显提高催化剂醇的明空收率(STY)、CO转化率,而总醇选择性不变.当活性组分Cu、Fe及助剂Co的质量分数分别为25%、22%、3%时,催化剂醇的时空收率高达205.6 g·kg^(-1)·h^(-1),CO转化率为56.6%.XRD、XPS和TPR结果表明:在Cu组分含量不变时,少量Co组分的引入使催化剂表面形成微量的CuFe_2O_4相,促进了Cu-Fe组分间相互作用的增强,改善了催化剂活性组分的分散度,有利于提高催化剂活性及醇的时空收率;随Co含量的增大,催化剂中金属组分间的相互作用发生转变,形成了Cu-Co尖晶石相,导致催化剂的醇选择性有所下降.

Cu/SiO_2、Fe/SiO_2和Cu-Fe/SiO_2催化乙酸气相加氢反应的研究

以硝酸铜和硝酸铁为金属前驱体采用等体积浸渍法制备了Cu/Si O_2、Fe/Si O_2和Cu-Fe/Si O_2催化剂,用于催化乙酸气相加氢生成乙醇和乙酸乙酯。在320℃、2.0 MPa、乙酸液时空速0.6 h^(-1)、氢酸摩尔比为5的条件下,Cu-Fe/Si O_2双金属催化剂对乙醇和乙酸乙酯的总选择性达到了93.5%,明显高于Cu/Si O_2和Fe/Si O_2单金属催化剂。同时,C_3产物(丙烷、丙烯、丙酮和异丙醇)、CO_2以及CH_4、CO、C_2H_6和C_2H_4等不凝性气体在双金属催化剂上得到了显著的抑制。对催化剂进行了透射电镜(TEM)、X射线衍射(XRD)、氢气-程序升温还原(H_2-TPR)和X射线光电能谱(XPS)表征分析,结果表明双金属催化剂上的Cu^0与铁的氧化物之间的协同作用是催化剂具有优越催化性能的主要原因。

石墨粒度对Cu-Fe基摩擦材料性能的影响

采用 MM- 10 0 0型摩擦磨损试验机研究了石墨粒度对 Cu- Fe基摩擦材料性能的影响 .研究结果表明 :随着石墨粒度的细化 ,材料的硬度提高而强度降低 ;材料及偶件的磨损增大 ;此外 ,石墨粒度对 Cu-