Cu-Co bi-metal catalyst prepared by perovskite CuO/LaCoO3 used for higher alcohol synthesis from syngas

Cu-Co bi-metal catalysts derived from CuO/LaCoO₃ perovskite structure were prepared by one-step citrate complexing method, and the structure evolution reaction from CuO/LaCoO₃ to Cu-Co₂C/La₂O₂CO₃ under H₂ pretreatment was investigated by techniques of XRD, TPR and TEM. The results suggest that a much higher dispersion of copper significantly enhanced the reduction of cobalt, and a stronger interaction between copper and cobalt ions in LaCoO₃ particles led to the formation of bi-metallic Cu-Co particles in the reduced catalysts and the enrichment of Co on the surface of bimetallic particles. The prepared catalysts were highly active and selective for the alcohol synthesis from syngas due to the presence of copper-modified Co₂C species.     

Low-temperature Catalytic Reduction of Nitrogen Monoxide with Carbon Monoxide on Copper Iron and Copper Cobalt Composite Oxides

Copper iron composite oxides (CuO/Fe2O3) and copper cobalt composite oxides (CuO/Co3O4) for the catalytic reduction of NO with CO at low temperature were prepared by co-precipitation. The catalytic activity and thermal stability of the catalysts were evaluated by a microreactor-GC system. The 100% conversion temperatures of NO are 80 oC for CuO/Fe2O3 and 90 oC for CuO/Co3O4. The catalysts possess high catalytic activity and favorable thermal stability for NO reduction with CO in a wide temperature range and long time range. A systematic study of the molar ratios of the reactants, the volume of NaOH, aging time, and calcination temperature/time was carried out to investigate the influence preparation conditions on the catalytic activity of the catalysts.     

CuxCo1-x/Al2O3/堇青石整体式催化剂的制备及其催化甲苯燃烧性能

以堇青石蜂窝陶瓷为基底,A12O3浆料为过渡胶体,Cu和Co为催化活性组分,制备了一系列CuxCo1-x/Al2O3/堇青石(x=0～1)整体式催化剂.采用X射线衍射、X射线光电子能谱、扫描电镜和程序升温还原等手段对催化剂进行了表征.以甲苯为模型化合物.在微型固定床反应器上评价了催化剂的催化性能.结果表明,当Cu含量较...     

CO/H_2合成混合醇Cu-Co-Fe催化剂的组成和铁的分散行为(英文)

Cu-Co-Fe catalysts were prepared by coprecipitation of Cu-Co nitrate solutions with Na2CO3 and impregnation of iron nitrate on the Cu-Co precipitates by incipient wetness method; and their phase structure, composition and iron dispersion behavior were studied by XRD, SEM and SAM techniques. The catalyst precursor consists of CuO, Co3O4 and (-Fe2O3. The intensity of XRD peak of Fe2O3 changes as the relative content of iron varies. No X-ray diffraction peak of iron oxide appears unless the content of iron surpasses a threshold value.     

Preparation and characterization of copper-doped cobalt oxide electrodes

Cobalt oxide (Co3O4) and copper-doped cobalt oxide (CuxCo(3-x)O4) films have been prepared onto titanium support by the thermal decomposition method. The electrodes have been characterized by different techniques such as cyclic voltammetry, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The effect on the electrochemical and crystallographic properties and surface morphology of the amount of copper in the oxide layer has been analyzed. The XPS spectra correspond to a characteristic monophasic Cu-Co spinel oxides when x is below 1. However, when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuO phase segregates at the surface. The analysis of the surface cation distribution indicates that Cu(II) has preference for octahedral sites.     

X-ray absorption spectroscopy of Mn/Co/TiO2 Fischer-Tropsch catalysts: relationships between preparation method, molecular structure, and catalyst performance

The effects of the addition of manganese to a series of TiO(2)-supported cobalt Fischer-Tropsch (FT) catalysts prepared by different methods were studied by a combination of X-ray diffraction (XRD), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and in situ X-ray absorption fine structure (XAFS) spectroscopy at the Co and Mn K-edges. After calcination, the catalysts were generally composed of large Co(3)O(4) clusters in the range 15-35 nm and a MnO(2)-type phase, which existed either dispersed on the TiO(2) surface or covering the Co(3)O(4) particles. Manganese was also found to coexist with the Co(3)O(4) in the form of Co(3-x)Mn(x)O(4) solutions, as revealed by XRD and XAFS. Characterization of the catalysts after H(2) reduction at 350 degrees C by XAFS and TEM showed mostly the formation of very small Co(0) particles (around 2-6 nm), indicating that the cobalt phase tends to redisperse during the reduction process from Co(3)O(4) to Co(0). The presence of manganese was found to hamper the cobalt reducibility, with this effect being more severe when Co(3-x)Mn(x)O(4) solutions were initially present in the catalyst precursors. Moreover, the presence of manganese generally led to the formation of larger cobalt agglomerates ( approximately 8-15 nm) upon reduction, probably as a consequence of the decrease in cobalt reducibility. The XAFS results revealed that all reduced catalysts contained manganese entirely in a Mn(2+) state, and two well-distinguished compounds could be identified: (1) a highly dispersed Ti(2)MnO(4)-type phase located at the TiO(2) surface and (2) a less dispersed MnO phase being in the proximity of the cobalt particles. Furthermore, the MnO was also found to exist partially mixed with a CoO phase in the form of rock-salt Mn(1-x)Co(x)O-type solid solutions. The existence of the later solutions was further confirmed by scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) for a Mn-rich sample. Finally, the cobalt active site composition in the catalysts after reduction at 300 and 350 degrees C was linked to the catalytic performances obtained under reaction conditions of 220 degrees C, 1 bar, and H(2)/CO = 2. The catalysts with larger Co(0) particles ( approximately >5 nm) and lower Co reduction extents displayed a higher intrinsic hydrogenation activity and a longer catalyst lifetime. Interestingly, the MnO and Mn(1-x)Co(x)O species effectively promoted these larger Co(0) particles by increasing the C(5+) selectivity and decreasing the CH(4) production, while they did not significantly influence the selectivity of the catalysts containing very small Co(0) particles.     

微乳液合成胶体CuO/γ-Al2O3及其催化芳香硝基化合物还原（英文）

Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.     

Cu改性ZIF-67衍生的Co3O4/C催化剂的CO-SCR脱硝特性

采用CO气体对NO进行选择性催化还原(CO-SCR)是一种有前景的脱硝技术.目前已报道的CO-SCR催化剂的脱硝特性主要是在无氧条件下开展的研究,考虑到实际应用情况,探究一种在有氧环境中具有较高脱硝效率的催化剂是很有必要的.作为一种新型功能性材料的金属有机骨架是脱硝催化剂的优良载体,其中ZIFs系列具有优良的性能.引入Cu对ZIF-67衍生的Co₃O₄/C进行改性,通过浸渍法在载体上负载铜后,热解氧化获得一系列CuO_x/Co₃O₄/C催化剂.利用ICP、 SEM、 XRD、 TEM、 TGA、 XPS、 BET和H₂-TPR等技术对催化剂的物理化学性质进行表征,结果表明,由于Cu的引入增加了表面的氧空位,改善了氧化还原能力,进而提高了催化剂脱硝活性.在制备的一系列催化剂中, 8.0 CuO_x/Co₃O₄/C在300℃时即可达到约95%NO转化率,并且其N₂选择性也达到9...     

Comparing the deactivation behaviour of Co/CNT and Co/γ-Al2O3 nano catalysts in Fischer-Tropsch synthesis

An extensive study of Fischer-Tropsch (FT) synthesis on cobalt nano particles supported on γ-alumina and carbon nanotubes (CNTs) catalysts is reported.20 wt% of cobalt is loaded on the supports by impregnation method.The deactivation of the two catalysts was studied at 220 C,2 MPa and 2.7 L/h feed flow rate using a fixed bed micro-reactor.The calcined fresh and used catalysts were characterized extensively and different sources of catalyst deactivation were identified.Formation of cobalt-support mixed oxides in the form of xCoO yAl2O3 and cobalt aluminates formation were the main sources of the Co/γ-Al2O3 catalyst deactivation.However sintering and cluster growth of cobalt nano particles are the main sources of the Co/CNTs catalyst deactivation.In the case of the Co/γ-Al2O3 catalyst,after 720 h on stream of continuous FT synthesis the average cobalt nano particles diameter increased from 15.9 to 18.4 nm,whereas,under the same reaction conditions the average cobalt nano particles diameter of the Co/CNTs increased from 11.2 to 17.8 nm.Although,the initial FT activity of the Co/CNTs was 26% higher than that of the Co/γ-Al2O3,the FT activity over the Co/CNTs after 720 h on stream decreased by 49% and that over the Co/γ-Al2O3 by 32%.For the Co/γ-Al2O3 catalyst 6.7% of total activity loss and for the Co/CNTs catalyst 11.6% of total activity loss cannot be recovered after regeneration of the catalyst at the same conditions of the first regeneration step.It is concluded that using CNTs as cobalt catalyst support is beneficial in carbon utilization as compared to γ-Al2O3 support,but the Co/CNTs catalyst is more susceptible for deactivation.     

锆改性钴基费-托合成催化剂催化性能的研究

 考察了助剂锆和金属钴负载量对锆改性Co／Al2O3催化剂催化性能的影响．结果表明，锆助剂能够高度分散在氧化铝载体上，而活性组分钴以一定尺寸存在；锆的添加能够明显地提高Co／Al2O3催化剂的催化活性和C5＋烃选择性，但助剂锆含量对催化剂催化性能的影响不大；在锆存在下，催化剂的催化活性随金属钴含量先升高后降低．进一步的研究表明，催化剂上烃形成速率的提高可能是由于锆助剂能够增加催化剂的活性位数目，增强桥式CO吸附的强度，在Co－ZrO2间形成界面．     

用不同前驱体制备的Co/SiO2催化剂的结构及其CO2/CH4重整反应性能

 分别采用硝酸钴、醋酸钴、硫酸钴和氯化钴为前驱体制备了Co／SiO2催化剂,用XRD,TPR,SEM和H2－TPD等实验技术考察了钴盐前驱体对催化剂结构和二氧化碳重整甲烷反应性能的影响,重点考察了硝酸钴和醋酸钴的作用．结果表明,由醋酸钴制备的Co／SiO2催化剂有最佳的催化活性和稳定性,它在钴物种的存在状态、金属－载体相互作用、钴金属晶粒度及抗烧结、抗积炭能力等方面,均与由硝酸钴制备的Co／SiO2催化剂存在显著的差别．Co／SiO2催化剂的反应活性和稳定性分别与其金属分散度和抗烧结、抗积炭能力密切相关．     

不同方法制备的CeO2载体对CuO/CeO2催化剂水煤气变换活性和稳定性的影响

分别采用沉淀法(A), 水热法(B)和柠檬酸溶胶-凝胶法(C)制备了三种CeO2材料, 并以其为载体采用沉积-沉淀法制备了CuO/CeO2催化剂. 运用N2物理吸附、粉末X射线衍射(PXRD)、原位粉末X射线衍射(in situ PXRD)、氢气-程序升温还原(H2-TPR)和循环伏安法(CV)等技术对其进行了表征, 考察了不同方法制备的CeO2载体对CuO/CeO2水煤气变换(WGS)催化剂的结构、氧化-还原性能、催化活性和稳定性的影响. 结果表明, 它们的催化活性和稳定性顺序都是CuO/CeO2-A>CuO/CeO2-B>CuO/CeO2-C. 联系表征结果, CuO/CeO2催化剂的活性与催化剂中CuO的颗粒度、CuO的微观应力和中等大小且与二氧化铈相互作用的CuO的数量等有关, 而这些因素很大程度上受CeO2载体本身的热稳定性的影响. 根据CV中扫描次数的增加, Cu2+←→Cu0氧化还原峰面积减小, 推断CuO/CeO2催化剂在一定条件下氧化还原是不可逆的, 这可能是其在反应气氛下经受温度循环之后活性降低的原因.     

不同方法制备的CeO2载体对CuO/CeO2催化剂水煤气变换活性和稳定性的影响

分别采用沉淀法(A),水热法(B)和柠檬酸溶胶-凝胶法(C)制备了三种CeO2材料,并以其为载体采用沉积-沉淀法制备了CuO/CeO2催化剂.运用N2物理吸附、粉末X射线衍射(PXRD)、原位粉末X射线衍射(in situ PXRD)、氢气-程序升温还原(H2-TPR)和循环伏安法(CV)等技术对其进行了表征,考察了不同方法制备的CeO2载体对CuO/CeO2水煤气变换(WGS)催化剂的结构、氧化-还原性能、催化活性和稳定性的影响.结果表明,它们的催化活性和稳定性顺序都是CuO/CeO2-A＞CuO/CeO2-B＞CuO/CeO2-C.联系表征结果,CuO/CeO2催化剂的活性与催化剂中CuO的颗粒度、CuO的微观应力和中等大小且与二氧化铈相互作用的CuO的数量等有关,而这些因素很大程度上受CeO2载体本身的热稳定性的影响.根据CV中扫描次数的增加,Cu2+←→Cu0氧化还原峰面积减小,推断CuO/CeO2催化剂在一定条件下氧化还原是不可逆的,这可能是其在反应气氛下经受温度循环之后活性降低的原因.     

碳纳米管负载Cu-Co复合氧化物的富氢气氛中CO催化消除

采用超声处理辅助浸渍法制备了多壁碳纳米管负载的Cu-Co复合氧化物催化剂. 利用XRD、TEM、H2-TPR、XPS和Raman光谱等表征了催化剂的结构性质. 在Cu和Co氧化物以及金属氧化物与碳纳米管载体间存在强相互作用. 催化剂在富氢气氛中CO催化消除反应中,与单一Cu或Co催化剂相比,Cu-Co复合氧化物催化剂表现出独特的反应特性,特别是在较高反应温度下可同时结合CO优先氧化和CO甲烷化的反应途径来实现高效CO消除. 当Cu/Co比为1/8时活性最优,可以实现在150-250℃和高反应空速 （120 L/（h·g））富氢气氛中CO的完全消除.     

Effect of support and cobalt precursors on the activity of Co/AlPO4 catalysts in Fischer–Tropsch synthesis

Cobalt supported on amorphous aluminum phosphate (Co/AlPO₄) catalysts were prepared by the impregnation method using three different cobalt precursors such as cobalt nitrate, acetate and chloride to elucidate the activity of Fischer–Tropsch synthesis. The use of AlPO₄ as a support for cobalt-based catalysts exhibits better catalytic performance during FTS reaction than the corresponding Co/Al₂O₃ catalyst. TPR results also suggest that the reducibility of the catalysts varies with the nature of cobalt precursors employed during the impregnation on AlPO₄ support. The Co/AlPO₄ catalyst prepared from cobalt nitrate shows higher CO conversion and C₈+ selectivity than the others due to the facile formation of homogeneous cobalt particles with proper electronic characters and high reducibility. Interestingly, all Co/AlPO₄ showed a growth of filamentous carbon initiated from the large mobile cobalt particles during the reaction. The differences in catalytic properties of Co/AlPO₄ are mainly attributed to the cobalt particle size, reducibility with different electronic states of metallic cobalt, pore diameter of AlPO₄ and formation of filamentous carbon.     

Cu-Co负载量对Cu-Co基催化剂催化CH4-合成气梯阶转化合成C2+含氧化合物的影响

以TiO₂纳米粒子为载体, 采用等体积浸渍法制备了Cu-Co双金属催化剂, 考察了不同Cu/Co质量比和不同Cu-Co含量的双金属催化剂对CH₄-合成气梯阶转化直接合成C₂⁺含氧化合物的影响. 在连续式步阶固定床反应装置上进行了催化性能评价. 实验结果表明, 当Cu-Co含量为18%, Cu/Co质量比为2: 1时, Cu-Co/TiO₂的C₂⁺含氧化合物产物的时空收率最大, 为19.92 mg·g_cat^-1·h^-1, 选择性为67.76%. 研究表明, 金属组分之间和载体与金属组分之间的相互作用、 金属组分良好的分散性和还原性是促进活性位的形成和提高催化剂活性的原因; 催化剂表面高度分散的CuO微晶有利于催化加氢和脱氢反应的进行, 对CH₄-合成气转化反应有重要的促进作用. 另外, 弱酸和中强酸有利于CH₄-合成气转化反应, 而强酸对该反应有抑制作用.     

混合钴源对Co-Pd/TiO2催化剂催化CH4-CO2两步梯阶转化法合成乙酸的性能影响

以混合钴源为前驱体, 采用等体积浸渍法制备了Co-Pd/TiO2催化剂, 考察了其对CH4和CO2梯阶转化直接合成乙酸的催化性能, 采用XRD, XPS, NH3-TPD和BET对催化剂进行了表征. 结果表明, 催化剂具有适宜的表面酸性、 高比表面积和孔结构, 有利于提高催化剂的活性. 在m(CoCl2)∶m=2∶5, m(Co)∶m(Pd)=2∶1, 常压, 150 ℃条件下, 乙酸的生成速率达到6.13 mg·g-1Cat·h-1, 选择性达到 81.6%, 分别比以单一Co源制备的催化剂提高了134%和16%.     

Influence of the pore structure of MCM-41 and SBA-15 silica fibers on atomic layer chemical vapor deposition of cobalt carbonyl

Mesoporous high surface area MCM-41 and SBA-15 type silica materials with fibrous morphology were synthesized and used as support materials for the ALCVD (atomic layer chemical vapor deposition) preparation of Co/MCM-41 and Co/SBA-15 catalysts. Co/MCM-41 and Co/SBA-15 catalysts were prepared by deposition of Co2(CO)8 from the gas phase onto the surfaces of preheated support materials in a fluidized bed reactor. For both silica materials, two different kinds of preparation methods, direct deposition and a pulse deposition method, were used. Pure silica supports as well as supported cobalt catalysts were characterized by various spectroscopic (IR) and analytical (X-ray diffraction, Brunauer-Emmett-Teller, elemental analysis) methods. MCM-41 and SBA-15 fibers showed considerable ability to adsorb Co2(CO)8 from the gas phase. For MCM-41 and SBA-15 silicas, cobalt loadings of 13.7 and 12.1 wt % were obtained using the direct deposition method. The cobalt loadings increased to 23.0 and 20.7 wt % for MCM-41 and SBA-15 silicas, respectively, when the pulse deposition method was used. The reduction behavior of silica-supported cobalt catalysts was found to depend on the catalyst preparation method and on the mesoporous structure of the support material. Almost identical reduction properties of SBA-15-supported catalysts prepared by different deposition methods are explained by the structural properties of the mesoporous support and, in particular, by the chemical structure of the inner surfaces and walls of the mesopores. Pulse O2/H2 chemisorption experiments showed catalytically promising redox properties and surface stability of the prepared MCM-41- and SBA-15-supported cobalt catalysts.     

钙钛矿结构在CO还原SO2催化脱硫中的作用

通过对钴和镧的单一氧化物、混合氧化物及具有钙钛矿结构的复合氧化物（ＬａＣｏＯ３等）上ＣＯ还原ＳＯ２脱硫反应的活性以及钴镧氧化物在反应条件下活化过程的考察，指出钙钛矿结构促进了活性晶相ＬａＯ２Ｓ和ＣｏＳ２的生成，增强了钴和镧在活化硫化及脱硫反应中的协同效应。     

LaCoO3 acting as an efficient and robust catalyst for photocatalytic water oxidation with persulfate

Cobalt-containing metal oxides [perovskites (LaCoO(3), NdCoO(3), YCoO(3), La(0.7)Sr(0.3)CoO(3)), spinel (Co(3)O(4)) and wolframite (CoWO(4))] have been examined as catalysts for photocatalytic water oxidation with Na(2)S(2)O(8) and [Ru(bpy)(3)](2+) as an electron acceptor and a photosensitizer, respectively. Catalysts with the perovskite structure exhibited higher catalytic activity as compared with the catalysts with the spinel and wolframite structures. LaCoO(3), which stabilizes Co(III) species in the perovskite structure, exhibited the highest catalytic activity in the photocatalytic water oxidation compared with CoWO(4), Co(3)O(4) and La(0.7)Sr(0.3)CoO(3) which contain Co(II) or Co(IV) species in the matrices. The high catalytic reactivity of LaCoO(3) possessing perovskite structure was maintained in NdCoO(3) and YCoO(3) which exclusively contain Co(III) species. Thus, the catalytic activity of Co ions can be controlled by the additional metal ions, which leads to development of highly reactive and robust catalysts for the photocatalytic water oxidation.