期刊文献+
共找到690篇文章
< 1 2 35 >
每页显示 20 50 100
Glycerol steam reforming over calcium hydroxyapatite supported cobalt and cobalt-cerium catalysts 被引量:5
1
作者 J.Dobosz M.Cichy +1 位作者 M.Zawadzki T.Borowiecki 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2018年第2期404-412,共9页
Calcium hydroxyapatite(HAp) supported cobalt and cobalt-cerium catalysts were examined for hydrogen production in glycerol steam reforming. The catalysts were synthesized by incipient wetness impregnation method and... Calcium hydroxyapatite(HAp) supported cobalt and cobalt-cerium catalysts were examined for hydrogen production in glycerol steam reforming. The catalysts were synthesized by incipient wetness impregnation method and characterized through X-ray diffraction, adsorption-desorption isotherms of N2 and temperature-programmed reduction of H2. Catalytic properties were examined in terms of glycerol conversion, selectivity toward hydrogen and C-containing products in temperature range of 650-800 ℃.The effect of active metal reduction and residence time(thereby flow feed rate) was analysed. It was found that the growth of residence time increased the hydrogen selectivity in the whole temperatures range whereas the catalyst reduction, before the catalytic process, decreased the hydrogen selectivity at temperatures lower than 750 ℃. The cerium addition improved the catalytic behaviour for hydrogen production via glycerol steam reforming. Cerium oxide suppressed the sintering of cobalt particles and as a result Co-Ce/HAp ensured higher stability and H2 selectivity than Co/HAp. Under reaction conditions investigated in this study, the highest selectivity toward hydrogen at 650 ℃ was obtained for 7.5 Co-Ce/HAp catalyst. 展开更多
关键词 Calcium hydroxyapatite cobalt catalysts cobalt-cerium catalysts Glycerol steam reforming
下载PDF
Ti-Si composite oxide-supported cobalt catalysts for CO_2 hydrogenation 被引量:4
2
作者 Jakrapan Janlamool Piyasan Praserthdam Bunjerd Jongsomjit 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第5期558-564,共7页
In the present work, different silica-based supported cobalt (Co) catalysts were synthesized and used for CO2 hydrogenation for methanation. Different supports, such as SSP, MCM-41, TiSSP and TiMCM were used to prep... In the present work, different silica-based supported cobalt (Co) catalysts were synthesized and used for CO2 hydrogenation for methanation. Different supports, such as SSP, MCM-41, TiSSP and TiMCM were used to prepare Co catalysts with 20 wt% Co loading. The supports and catalysts were characterized by means of N2 physisorption, XRD, SEM/EDX, XPS, TPR and CO chemisorption. It is found that after calcination of catalysts, Ti is present in the form of anatase. The introduction of Ti plays important roles in the properties of Co catalysts by:(i) facilitating the reduction of Co oxides species which are strongly interacted with support, (ii) preventing the formation of silicate compounds, and (iii) inhibiting the RWGS reaction. Based on CO2 hydrogenation, the CoTiMCM catalyst exhibites the highest activity and stability. 展开更多
关键词 CO2 hydrogenation TITANIA-SILICA cobalt catalysts METHANATION
下载PDF
Effects of the Different Supports on the Activity and Selectivity of Iron-Cobalt Bimetallic Catalyst for Fischer-Tropsch Synthesis 被引量:3
3
作者 Xiangdong Ma Qiwen Sun +2 位作者 Fahai Cao Weiyong Ying Dingye Fang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2006年第4期335-339,共5页
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-program... 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. 展开更多
关键词 Fischer-Tropsch synthesis bimetallic catalyst iron cobalt support silica ALUMINA active carbon SYNGAS
下载PDF
Kinetics and product distribution studies on ruthenium-promoted cobalt/alumina Fischer-Tropsch synthesis catalyst 被引量:3
4
作者 Ahmad Tavasoli Ali Nakhaei Pour Masoumeh Ghalbi Ahangari 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2010年第6期653-659,共7页
Hydrocarbon production rates and distributions on ruthenium promoted alumina supported cobalt Fischer-Tropsch synthesis (FTS) catalyst were studied by the concept of two superimposed Anderson-Schulz-Flory (ASF) di... Hydrocarbon production rates and distributions on ruthenium promoted alumina supported cobalt Fischer-Tropsch synthesis (FTS) catalyst were studied by the concept of two superimposed Anderson-Schulz-Flory (ASF) distributions.The results indicated that the characterizing growth probabilities α1 and α2 were strongly dependent on reaction conditions.By increasing the H2 /CO partial pressure ratios and reaction temperatures,deviation from normal ASF distribution decreases and the double-α-ASF distribution changes into a straight line.Based on the concept of double-α-ASF distribution,a useful rate equation for the production of hydrocarbons under industrial reaction conditions is obtained. 展开更多
关键词 Fischer-Tropsch synthesis cobalt catalyst RUTHENIUM reaction rate products distribution
下载PDF
Preparation and catalytic behavior of reduced graphene oxide supported cobalt oxide hybrid nanocatalysts for CO oxidation 被引量:4
5
作者 Yan WANG Ze-hua CHEN +6 位作者 Jing HUANG Gao-jie LI Jian-liang CAO Bo ZHANG Xing-ying CHEN Huo-li ZHANG Lei JIA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第11期2266-2274,共9页
The reduced graphene oxide (rGO) supported cobalt oxide nanocatalysts were prepared by the conventional precipitationand hydrothermal method. The as-prepared rGO-Co3O4 was characterized by the XRD, Raman spectrum, S... The reduced graphene oxide (rGO) supported cobalt oxide nanocatalysts were prepared by the conventional precipitationand hydrothermal method. The as-prepared rGO-Co3O4 was characterized by the XRD, Raman spectrum, SEM, TEM, N2-sorption,UV-Vis, XPS and H2-TPR measurements. The results show that the spinel cobalt oxide nanoparticles are highly fragmented on therGO support and possess uniform particle size, and the as-prepared catalysts possess high specific surface area and narrow pore sizedistribution. The catalytic properties of the as-prepared rGO-Co3O4 catalysts for CO oxidation were evaluated through acontinuous-flow fixed-bed microreactor-gas chromatograph system. The catalyst with 30% (mass fraction) reduced graphene oxideexhibits the highest activity for CO complete oxidation at 100 ℃. 展开更多
关键词 reduced graphene oxide cobalt oxide catalyst CO oxidation catalytic activity
下载PDF
Effect of the support on cobalt carbide catalysts for sustainable production of olefins from syngas 被引量:4
6
作者 Xinxing Wang Wen Chen +7 位作者 Tiejun Lin Jie Li Fei Yu Yunlei An Yuanyuan Dai Hui Wang Liangshu Zhong Yuhan Sun 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第12期1869-1880,共12页
Co2C‐based catalysts with SiO2,γ‐Al2O3,and carbon nanotubes(CNTs)as support materials were prepared and evaluated for the Fischer‐Tropsch to olefin(FTO)reaction.The combination of catalytic performance and structu... Co2C‐based catalysts with SiO2,γ‐Al2O3,and carbon nanotubes(CNTs)as support materials were prepared and evaluated for the Fischer‐Tropsch to olefin(FTO)reaction.The combination of catalytic performance and structure characterization indicates that the cobalt‐support interaction has a great influence on the Co2C morphology and catalytic performance.The CNT support facilitates the formation of a CoMn composite oxide during calcination,and Co2C nanoprisms were observed in the spent catalysts,resulting in a product distribution that greatly deviates from the classical Anderson‐Schulz‐Flory(ASF)distribution,where only 2.4 C%methane was generated.The Co3O4 phase for SiO2‐andγ‐Al2O3‐supported catalysts was observed in the calcined sample.After reduction,CoO,MnO,and low‐valence CoMn composite oxide were generated in theγ‐Al2O3‐supported sample,and both Co2C nanospheres and nanoprisms were identified in the corresponding spent catalyst.However,only separated phases of CoO and MnO were found in the reduced sample supported by SiO2,and Co2C nanospheres were detected in the spent catalyst without the evidence of any Co2C nanoprisms.The Co2C nanospheres led to a relatively high methane selectivity of 5.8 C%and 12.0 C%of theγ‐Al2O3‐and SiO2‐supported catalysts,respectively.These results suggest that a relatively weak cobalt‐support interaction is necessary for the formation of the CoMn composite oxide during calcination,which benefits the formation of Co2C nanoprisms with promising catalytic performance for the sustainable production of olefins via syngas. 展开更多
关键词 Fischer‐Tropsch to olefins cobalt carbide Supported catalyst OLEFIN SYNGAS
下载PDF
Fischer–Tropsch synthesis on impregnated cobalt-based catalysts:New insights into the effect of impregnation solutions and pH value 被引量:1
7
作者 Chuang Xing Peipei Ai +6 位作者 Peipei Zhang Xinhua Gao Ruiqin Yang Noriyuki Yamane Jian Sun Prasert Reubroycharoen Noritatsu Tsubaki 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期994-1000,共7页
The Co-based catalysts were prepared with different cobalt acetate solutions. Effects of pH value were studied deeply on Fischer–Tropsch synthesis (FTS) through a semi-batch reactor. Among all impregnation solutions ... The Co-based catalysts were prepared with different cobalt acetate solutions. Effects of pH value were studied deeply on Fischer–Tropsch synthesis (FTS) through a semi-batch reactor. Among all impregnation solutions (water, butanol, amyl alcohol, acetic acid, nitric acid and ammonium nitrate), the catalyst prepared by NH4NO3solution showed the highest catalytic activity due to its small particle size and high reduction degree. However, the catalyst with the smallest particle size derived from water as impregnation solution exhibited low activity as well as high methane selectivity since it was difficult to be reduced and inactive in FTS. According to FT-IR spectra results, the low intensity of absorbed CO on the catalyst prepared from water solution resulted in low FTS activity. Whereas, the high activity of catalysts prepared from NH4NO3solution could be explained by the high intensity of absorbed CO on the catalysts. The cobalt species on the catalysts prepared under lower pH conditions exhibited smaller particle size distribution as well as lower CO conversion than those prepared at higher pH value. © 2016 Science Press 展开更多
关键词 Batch reactors catalyst selectivity catalystS cobalt IMPREGNATION Particle size Particle size analysis pH pH effects
下载PDF
Synthesis and characterization of multiwall carbon nanotubes/alumina nanohybrid-supported cobalt catalyst in Fischer-Tropsch synthesis 被引量:1
8
作者 Ali Karimi Bahram Nasernejad Ali Morad Rashidi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第4期582-590,共9页
Multiwall carbon nanotubes (MWNTs) and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis (FTS) catalyst support. Alumina nano-particles (10 wt%) were introduced directly on funct... Multiwall carbon nanotubes (MWNTs) and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis (FTS) catalyst support. Alumina nano-particles (10 wt%) were introduced directly on functionalized MWNTs by a modified sol-gel method. Microstructure observations show that alumina particles were homogeneously dispersed on the inside and outside of modified MWNTs surfaces. 15 wt% cobalt loading catalysts were prepared with this nanohybrid and γ-alumina as a reference, using a sol-gel technique and wet impregnation method respectively. These catalysts were characterized by TEM, XRD, N2-adsorption, H2 chemisorption and TPR. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the MWNTs nanohybrid shift the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. Nanohybrid also aided in high dispersion of metal clusters and high stability and performance of catalyst. The proposed MWNTs nanohybrid-supported cobalt catalysts showed the improved FTS rate (gHc/(gcat.min)), CO conversion (%), and water gas shift rate (WGS)(gcoz/(gcat.h)) of 0.012, 52, and 30E-3, respectively, as compared to those of 0.007, 25, and 18E-3, respectively, on the γ-alumina-supported cobalt catalysts with the same Co loading. 展开更多
关键词 carbon nanotubes NANOHYBRID cobalt catalyst ALUMINA FT synthesis SOL-GEL
下载PDF
The Effective Catalyst (Cobalt Salt/Lewis Acid) for Beckmann Rearrangement of Cycloalkanone Oximes to Lactams under Mild Conditions 被引量:2
9
作者 Masahiro Komeda Ayana Ozaki +4 位作者 Keita Hayashi Michinori Sumimoto Kenji Hori Tsunemi Sugimoto Hidetoshi Yamamoto 《International Journal of Organic Chemistry》 2015年第2期57-62,共6页
The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a sat... The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts. 展开更多
关键词 Beckmann REARRANGEMENT Cycloalkanone OXIMES LACTAM cobalt catalysts Lewis ACIDS
下载PDF
Solvent-free synthesis of alumina supported cobalt catalysts for Fischer–Tropsch synthesis 被引量:1
10
作者 Mengnan Lu Nouria Fatah Andrei Y.Khodkov 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期1001-1007,共7页
A novel mechano-synthesis method has been elaborated in this work for the design of efficient cobalt-based Fischer–Tropsch catalysts. The process aims to reduce the total number of steps involved in the synthesis of ... A novel mechano-synthesis method has been elaborated in this work for the design of efficient cobalt-based Fischer–Tropsch catalysts. The process aims to reduce the total number of steps involved in the synthesis of solid catalysts and thus to avoid relevant toxic solutions generated during the catalyst preparation. The mechano-synthesis of the Co/Al2O3catalyst was processed in a low-energy vibratory micro mill and high energy planetary ball mill. Porous spherical γ-aluminas (1860 µm and 71 µm mean particle diameter) were used in this work as host compounds. Co3O4(3 µm mean particle diameter) has provided guest particles for mechano-synthesis. The catalysts were characterized by textural (surface area, porosity and particle size) and structural analyses (X-ray diffraction, TPR, SEM-EDX and microprobe). The microprobe images show deposition of Co3O4on the surface of the alumina and indicated no Co3O4diffusion inside the alumina pores. SEM-EDX mapping illustrated that cobalt coating tended to occur on surface of rounded shape of cracked alumina fragments. After milling, the crystallite size of Co3O4decreased to 15 nm from 30 to 50 nm. The TPR profiles indicated very low concentrations of inactive cobalt aluminate mixed compounds which are usually produced during the catalyst preparation by impregnation. In Fischer–Tropsch synthesis, the catalysts prepared using mechano-synthesis methods showed catalytic performance comparable to the catalysts prepared by impregnation. © 2016 Science Press 展开更多
关键词 ALUMINA Ball mills catalystS cobalt Crystallite size IMPREGNATION Particle size Particle size analysis X ray diffraction
下载PDF
Recent advances and perspectives in cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation 被引量:1
11
作者 Wanjun Sun Jiayu Zhu +5 位作者 Meiyu Zhang Xiangyu Meng Mengxue Chen Yu Feng Xinlong Chen Yong Ding 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第9期2273-2300,共28页
Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the gree... Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the greenhouse gas effect and countering energy crisis,which is an attractive and challenging topic.Hence,various types of photocatalysts have been developed successively to meet the requirements of these photocatalysis.Among them,cobalt‐based heterogeneous catalysts emerge as one of the most promising photocatalysts that open up alluring vistas in the field of solar‐to‐fuels conversion,which can effectively enhance photocatalytic efficiency by extending light absorption range,promoting charge separation,providing active sites,and lowering reaction barrier.In this review,we first present the working principles of cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation.Second,five efficient strategies including surface modification,morphology modulation,crystallinity controlling,crystal engineering and doping,are discussed for improving the photocatalytic performance with different types cobalt‐based catalysts(cobalt nanoparticles and single atom,oxides,sulfides,phosphides,MOFs,COFs,LDHs,carbide,and nitrides).Third,we outline the applications for the state‐of‐the‐art photocatalytic CO_(2) reduction and water splitting,and nitrogen fixation over cobalt‐based heterogeneous catalysts.Finally,the central challenges and possible improvements of cobalt‐based photocatalysis in the future are presented.The purpose of this review is to summarize the past experience and lessons,and provide reference for the further development of cobalt‐based photocatalysis technology. 展开更多
关键词 PHOTOCATALYSIS cobalt based heterogeneous catalyst Water splitting Carbon dioxide reduction Nitrogen fixation
下载PDF
Effects of TiO_(2) Support and Cobalt Addition of Ni/TiO_(2) Catalyst in Selective Hydrogenation of Furfural to Furfuryl Alcohol 被引量:1
12
作者 Kittithad Wonglekha Weerachon Tolek +4 位作者 Okorn Mekasuwandumrong Wasu Chaitree Piyasan Praserthdam Kiat Moon Lee Joongjai Panpranot 《Journal of Renewable Materials》 SCIE EI 2022年第8期2055-2072,共18页
An effect of phase compositions(rutile,Rut and anatase,Ant)of TiO_(2)supports on the selective hydrogenation of furfural to furfuryl alcohol was investigated.The 15%wt Ni/TiO_(2)catalysts were prepared by incipient im... An effect of phase compositions(rutile,Rut and anatase,Ant)of TiO_(2)supports on the selective hydrogenation of furfural to furfuryl alcohol was investigated.The 15%wt Ni/TiO_(2)catalysts were prepared by incipient impregnation method.The result showed that Ni supported on anatase-rutile mixed phase TiO_(2)(91%Rut and 9%Ant,A2)provided the highest furfuryl alcohol yield at 43.8%due to the relatively strong Ni-TiO_(2)interaction,its appropriate crystallite sizes,and high average pore sizes.Furthermore,the effect of cobalt as a promoter on Ni/TiO_(2)-A2 catalysts was studied.The result showed that the Ni-Co/TiO_(2)-A2 catalysts exhibited poorer catalyst performances compared to the monometallic Ni/TiO_(2),probably because addition of cobalt can lower the reduction temperatures of Ni/TiO_(2)and weaken the metal-support interaction. 展开更多
关键词 Ni catalyst furfural hydrogenation TiO_(2) furfuryl alcohol cobalt
下载PDF
Effect of cobalt loading on reducibility, dispersion and crystallite size of Co/Al_2O_3 Fischer-Tropsch catalyst 被引量:1
13
作者 熊海峰 张煜华 +1 位作者 李金林 古映莹 《Journal of Central South University of Technology》 2004年第4期414-418,共5页
Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means... Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen temperature programmed desorption (H2-TPD) and O2 titration. Co-support compound formation can be detected in catalyst system by XRD. For the Co/Al2O3 catalysts with low cobalt loading, CoAl2O4 phase appears visibly. Two different reduction regions can be presented for Co/Al2O3 catalysts, which belong to Co3O4 crystallites (reduction at 320 ℃) and cobalt oxide-alumina interaction species (reduction at above 400 ℃). Increasing Co loading results in the increase of Co3O4 crystallite size. The reduced Co/Al2O3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased. 展开更多
关键词 Fischer-Tropsch synthesis cobalt/alumina catalyst temperature programmed reduction hydrogen temperature programmed desorption
下载PDF
Fischer-Tropsch Synthesis over Alumina- Supported Cobalt-Based Catalysts: Effect of Support Variables 被引量:1
14
作者 Yan Liu Heqin Guo +6 位作者 Litao Jia Zhancheng Ma Yong Xiao Congbiao Chen Ming Xia Bo Hou Debao Li 《Journal of Materials Science and Chemical Engineering》 2014年第12期19-27,共9页
Different kinds of aluminum precursors were obtained from precipitating ammonium bicarbonate, ammonium carbonate, and saturated ammonium bicarbonate, then, boehmite (AlO(OH)), ammonium alumina carbonate hydroxide (AAC... Different kinds of aluminum precursors were obtained from precipitating ammonium bicarbonate, ammonium carbonate, and saturated ammonium bicarbonate, then, boehmite (AlO(OH)), ammonium alumina carbonate hydroxide (AACH) and their mixture were obtained, and then, different kinds of alumina were obtained after calcination. Three catalysts supported on the different alumina were obtained via impregnating cobalt and ruthenium by incipient wetness. The effects of different precipitants on composition of precursors were?studied by XRD, FTIR, and TGA. The property and structure of alumina were studied by XRD and BET. The supported catalysts were studied by characterizations of XRD and H2-TPR, and the catalytic performance for Fischer-Tropsch synthesis (FTS) were evaluated at a fix-bed reactor. The relations among the composition of precursors, the property of alumina and the catalytic performance of supported catalysts were researched thoroughly. 展开更多
关键词 cobalt-Based catalysts FISCHER-TROPSCH Synthesis ALUMINA PRECIPITANT
下载PDF
CO_2 Reforming of CH_4 over Nickel and Cobalt Catalysts Prepared from La-Based Perovskite Precursors
15
作者 Jianjun Guo, Hui Lou, Yinghong Zhu, Xiaoming ZhengInstitute of Catalysis, Zhejiang University, Hangzhou 310028, China 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2003年第1期17-22,共6页
Four perovskite-type complex oxides (LaNiO_3, La_2NiO_4, LaCoO_3 andLa_2CoO_4) were successfully prepared using two sol-gel methods, the Pechini method (PC) and thecitric acid complexing method (CC). The catalysts wer... Four perovskite-type complex oxides (LaNiO_3, La_2NiO_4, LaCoO_3 andLa_2CoO_4) were successfully prepared using two sol-gel methods, the Pechini method (PC) and thecitric acid complexing method (CC). The catalysts were characterized by XRD and TPR. Afterreduction, the activity of the catalysts in the CO_2 reforming of methane was tested. Ni-basedcatalysts from La_2NiO_4 precursors were the most active and stable catalyst after calcination above850 ℃, which gave a methane conversion of 0.025 mmol/(g·s) for those prepared by the PC methodand 0.020 mmol/(g·s) by the CC method. It was proposed that the well-defined structure and lowerreducibility is responsible for the unusual catalytic behavior observed over the pre-reducedLa2NiO_4 catalyst. 展开更多
关键词 carbon dioxide reforming METHANE SYNGAS perovskite oxide sol-gelpreparation nickel catalyst cobalt catalyst
下载PDF
Silicon Nitride Supported Cobalt Catalyst for Enhanced Hydrogen Production from Ethanol Steam Reforming
16
作者 LI Li LI Ruiling +5 位作者 XU Junjie MA Jinjin NI Jiaqi YAN Jing LIU Yi LU Lilin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2022年第6期1172-1179,共8页
Silicon nitride(Si_(3)N_(4))supported cobalt catalysts(Co/Si_(3)N_(4))were fabricated by using wetness impregnation procedure.The microscopic morphology,phase composition,and electronic states were characterized by XR... Silicon nitride(Si_(3)N_(4))supported cobalt catalysts(Co/Si_(3)N_(4))were fabricated by using wetness impregnation procedure.The microscopic morphology,phase composition,and electronic states were characterized by XRD,TEM,SEM,and XPS,respectively.For comparison,cobalt catalyst supported on SiO_(2)(Co/SiO_(2))was also investigated.XPS studies and DFT calculations show that the cobalt species in Co/Si_(3)N_(4) have lower valence state than those in Co/SiO_(2).The catalytic ESR reactions demonstrate that Co/Si_(3)N_(4) exhibits distinctly higher catalytic activity and hydrogen selectivity than Si_(3)N_(4) support and Co/SiO_(2) catalyst with the identical cobalt loading,indicative of the favorable effect of Si_(3)N_(4) support on the catalytic performance of supported cobalt catalyst.Durability tests and TG-DSC studies show that Co/Si_(3)N_(4) catalyst exhibits better stability and resistance to coke during the same catalytic experiment period. 展开更多
关键词 silicon nitride supported cobalt catalyst ethanol steam reforming reaction hydrogen production
下载PDF
Cobalt Recovery from Waste Catalysts (Petroleum Refining Industry from Gujarat)
17
作者 Palanivel Sivasakthi Natarajan Sathaiyan 《Open Journal of Metal》 2012年第1期24-30,共7页
A hydrometallurgical process has been developed for cobalt recovery from a waste catalyst (petroleum refining industry). This waste catalyst containing about 2.18 weight % of Co, is highly contaminated by Mg, Al, Si, ... A hydrometallurgical process has been developed for cobalt recovery from a waste catalyst (petroleum refining industry). This waste catalyst containing about 2.18 weight % of Co, is highly contaminated by Mg, Al, Si, Ca, Fe, Ni, Cu, Zn, Mo. The major steps are: (I) The spent catalyst is roasted with flux material in an electrical furnace at very high temperature (700?C) for a specific duration. (II) The roasted sample is leached with sulphuric acid to bring the metal contents into solution form. (III) For separating cobalt values from the leach solution, the solution pH is raised by NaOH addition, where all cobalt content is precipitated at a pH of about 12. (IV) This cobalt hydroxide precipitate is filtered and dissolved in minimum amount of sulphuric acid to get cobalt sulphate solution which is used as the electrolyte for the electrolytic recovery of cobalt. For optimizing various parameters like (1) H2SO4 concentration;(2) Duration;(3) Cobalt concentration;(4) Current density;(5) Temperature;(6) Stirring etc., The particle surface morphology and deposited layers have been characterized by scanning electron microscopy (SEM). A compact metallic deposit containing 70% cobalt was obtained. 展开更多
关键词 Hydrometallurgical ELECTROWINNING cobalt FLUX Material Waste catalysts H2SO4 LEACHING
下载PDF
CHARACTERIZATION OF COBALT SITES IN REDUCED Co-Mo/Al_2O_3 AND Ru-Co-Mo/Al_2O_3 CATALYSTS
18
作者 Fend Shou XIAO (Department of Chemistry,Jilin University,Changchun 130023)Qin XIN Xie Xian GUO (National Laboratory for Catalysis,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023) 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第7期581-582,共2页
The two Co sites are well characterized in reduced Co-Mo/Al_2O_3 and Ru-Co- Mo/Al_2O_3 by new bands at 1895 and 1880 cm^(-1)in the IR spectra due to NO adsorption.
关键词 Mo Co CO CHARACTERIZATION OF cobalt SITES IN REDUCED Co-Mo/Al2O3 AND Ru-Co-Mo/Al2O3 catalystS AL RU
下载PDF
Synthesis of Polymer-Supported Heteronuclear Rhodium- Cobalt Bimetallic Carbonyl Cluster Catalysts and Their Hydroformylation Properties
19
作者 He Binglin(Ho Ping-Lum), Sun Juntan, Li Hong, Sang Junjie and Zhao Fenzhi (Institute of Polymer Chemistry, Nankai University, Tianjin) 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1989年第4期357-362,共6页
Tetranuclear Rh-Co bimetallic cluster was synthesized and characterized by IR and XPS. The properties of the anchored catalysts, its stability and the ligand effect were also studied. The experimental results show tha... Tetranuclear Rh-Co bimetallic cluster was synthesized and characterized by IR and XPS. The properties of the anchored catalysts, its stability and the ligand effect were also studied. The experimental results show that the optimal conditions for the hydroformylation of hexene-1 are as follows: the temperature is 80℃, reaction time 8 h, pressure 5. 88×105 Pa, and molar ratio of H2/CO 1. 2/1. 0. Functional groups attached to the donor atom(N) possess more or less some influence on the catalytic behavior. Compared with the homogeneous cluster, the polymer-supported bimetallic cluster is more stable. After the catalytic reaction, the structure of the anchored catalysts was not destroyed. X-ray photoelectron spectroscopy characterization indicates that there is a weak interaction between the polymer support and the active metals. 展开更多
关键词 Rhodium-cobalt cluster Polymer-supported catalysts HYDROFORMYLATION
下载PDF
Characterization and catalytic behavior of EDTA modified silica nanosprings (NS)-supported cobalt catalyst for Fischer-Tropsch CO-hydrogenation
20
作者 Abdulbaset M.Alayat Elena Echeverria +1 位作者 David N.Mcllroy Armando G.McDonald 《燃料化学学报》 EI CAS CSCD 北大核心 2018年第8期957-966,共10页
The effect of ethylene diamine tetraacetic acid(EDTA) modification on the physico-chemical properties and catalytic performance of silica nanosprings(NS) supported cobalt(Co) catalyst was investigated in the conversio... The effect of ethylene diamine tetraacetic acid(EDTA) modification on the physico-chemical properties and catalytic performance of silica nanosprings(NS) supported cobalt(Co) catalyst was investigated in the conversion of syngas(H^(2+) CO) to hydrocarbons by Fischer-Tropsch synthesis(FTS). The unmodified Co/NS and modified Co/NS-EDTA catalysts were synthesized via an impregnation method. The prepared Co/NS and Co/NS-EDTA catalysts were characterized before the FTS reaction by BET surface area,X-ray diffraction(XRD),transmission electron microscopy(TEM),temperature programmed reduction(TPR),X-ray photoelectron spectroscopy(XPS),differential thermal analysis(DTA) and thermogravimetric analysis(TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. FTS was carried out in a quartz fixedbed microreactor(H_2/CO of 2 ∶1,230 ℃ and atmospheric pressure) and the products trapped and analyzed by GC-TCD and GC-MS to determine CO conversion and reaction selectivity. The experimental results indicated that the modified Co/NS-EDTA catalyst displayed a more-dispersed phase of Co_3O_4 nanoparticles(10.9%) and the Co_3O_4 average crystallite size was about 12.4 nm. The EDTA modified catalyst showed relatively higher CO conversion(70.3%) and selectivity toward C_(6-18)(JP-8,Jet A and diesel) than the Co/NS catalyst(C_(6-14))(JP-4). 展开更多
关键词 化学分析 煤矿 燃烧
下载PDF
上一页 1 2 35 下一页 到第
使用帮助 返回顶部