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Synthesis and characterization of multiwall carbon nanotubes/alumina nanohybrid-supported cobalt catalyst in Fischer-Tropsch synthesis

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Journal of Energy Chemistry 2013年第4期22卷 582-590页

作者： Ali Karimi Bahram Nasernejad Ali Morad Rashidi Chemical Engineering Department Amir Kabir University of Technology Nanotechnology Research Center Research Institute of Petroleum Industry

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.

关键词： carbon nanotubes nanohybrid cobalt catalyst alumina FT synthesis sol-gel

Fischer-Tropsch synthesis by reduced graphene oxide nanosheets supported cobalt catalysts: role of support and metal nanoparticle size on catalyst activity and products selectivity

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Frontiers of Chemical Science and Engineering 2021年第2期15卷 299-309页

作者： Hasan Oliaei Torshizi Ali Nakhaei Pour Ali Mohammadi Yahya Zamani Seyed Mehdi Kamali Shahri Department of Chemistry Faculty of ScienceFerdowsi University of MashhadMashhad ***Iran Gas Research Division Research Institute of Petroleum IndustryTehran ***Iran Department of Chemical Engineering Pennsylvania State UniversityState CollegePA 16801USA

In this paper,a series of cobalt catalysts supported on reduced graphene oxide(rGO)nanosheets with the loading of 5,15 and 30 wt-%were provided by the impregnation method.The activity of the prepared catalysts is evaluated in the Fischer-Tropsch synthesis(FTS).The prepared catalysts were carefully characterized by nitrogen adsorption-desorption,hydrogen chemisorption,X-ray diffraction,Fourier transform infrared spectroscopy,Raman spectroscopy,temperature programmed reduction,transmission electron microscopy,and field emission scanning electron microscopy techniques to confirm that cobalt particles were greatly dispersed on the rGO nanosheets.The results showed that with increasing the cobalt loading on the rGO support,the carbon defects are increased and as a consequence,the reduction of cobalt is decreased.The FTS activity results showed that the cobalt-time yield and turnover frequency passed from a maximum for catalyst with the Co0 average particle size of 15 nm due to the synergetic effect of cobalt reducibility and particle size.The products selectivity results indicated that the methane selectivity decreases,whereas the C5+selectivity raises with the increasing of the cobalt particle size,which can be explained by chain propagation in the primary chain growth reactions.

关键词： cobalt catalyst cobalt particle size Fischer-Tropsch synthesis reduced graphene oxide supported catalyst

Kinetics and product distribution studies on ruthenium-promoted cobalt/alumina Fischer-Tropsch synthesis catalyst

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Journal of Natural Gas Chemistry 2010年第6期19卷 653-659页

作者： Ahmad Tavasoli Ali Nakhaei Pour Masoumeh Ghalbi Ahangari School of chemistry College of scienceUniversity of Tehran Research Institute of Petroleum Industry

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.

关键词： Fischer-Tropsch synthesis cobalt catalyst ruthenium reaction rate products distribution

CARBON NANOTUBES VIA METHANE DECOMPOSITION ON AN ALUMINA SUPPORTED cobalt AEROGEL catalyst

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China Particuology 2003年第6期1卷 266-270页

作者： Lingyu Piao Jiuling Chen Yongdan Li Department of Catalysis Science and Technology School of Chemical EngineeringTianjin UniversityTianjin 300072P.R.China

An alumina-supported cobalt aerogel catalyst prepared from a sol-gel and a supercritical drying method was used in the catalytic decomposition of methane. The physical-chemical properties of the catalyst were characterized and its activity for methane decomposition was investigated. The effects of calcination and reaction temperatures on the activity of the catalyst and the morphology of the carbon nanotubes produced were discussed. A CoAl2O4 spinel structure formed in the calcined catalyst. The quantity of the nanotubes produced in the reaction increases with the amount of cobalt in the reduced catalyst. A higher reaction temperature leads to a higher reaction rate, though faster deactivation of the catalyst occurs with the change. The carbon nanotubes grown on the catalyst have smooth walls and uniform di-ameter distribution.

关键词： catalytic decomposition methane carbon nanotubes sol-gel aerogel cobalt catalyst morphology

Visible light-driven water oxidation using metal oxide quantum dots modified with a cobalt catalyst

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Visible light-driven water oxidation using metal oxide quant...

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

中国化学会第九届全国无机化学学术会议

作者： Fujun Niu Ning Zhang Shaohua Shen Liejin Guo International Research Center of Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong University

Conversion of sunlight to chemical fuels is the holy grail to deal with the energy and environment issue.1,2 Inspired by the natural photosynthesis, molecular based photocatalytic system has been widely investigated. Generally speaking, such a system contains three part: a sensitizer to absorb light, a reduction catalyst to generate H2, and an oxidation catalyst to produce O2. The oxidation of water has been proved to be the key of the entire water splitting process, as the reaction kinetic limitation step.3 In this work, we developed a novel system with Co3O4 quantum dots（QDs） or Fe2O3 QDs as photosensitizer, a salophen cobalt（II） complex（Co SLP） as catalyst, and persulfate（S2-2O8） as the sacrificial electron acceptor（Fig. 1）. The photocatalytic oxygen evolution rate of the systems were 75μmol/h/g and 84μmol/h/g over the cobalt（II） complex when Co3O4 QDs or Fe2O3 QDs was employed, respectively. While no O2 evolution were observed when either salophen cobalt（II） complex or QDs was absent. This high efficiency might be attributed to the interfacial hole transfer from photoexcited QDs to the cobalt（II） complex.

关键词： artificial photosynthesis oxygen production quantum dots cobalt catalyst

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CCS Chemistry 2022年第8期4卷 2782-2792页

作者： Lan Li Zhi-Bin Fang Wenzhuo Deng Jun-Dong Yi Rui Wang Tian-Fu Liu State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002 University of Chinese Academy of Sciences Beijing 100049 CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Key Laboratory of Nanomaterials Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002

Assembling the reactive low-cost Co clusters and photoresponsive ligands in the form of metal–organic frameworks(MOFs)is a promising strategy to construct efficient water-oxidizing photocatalysts,but it is restricted by poor water stability.Introducing high valent cations in the clusters to build heterometallic Co-MOFs might be a solution,yet a precise fabrication strategy is still challenging.

关键词： cobalt catalyst metal–organic frameworks single-site Ti incorporation stability photocatalytic O_(2)evolution

Bimetallic water oxidation: One-site catalysis with two-sites oxidation

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Journal of Energy Chemistry 2021年第12期30卷 1-7,I0001页

作者： Fei Xie Ming-Tian Zhang Center of Basic Molecular Science(CBMS) Department of ChemistryTsinghua UniversityBeijing 100084China

Water oxidation is the key half reaction to achieve full splitting of water to hydrogen and oxygen.Herein,a binuclear complex,[(L^(4-))Co_(2)~Ⅲ(OH)]ClO_(4),was reported as a stable and efficient homogenous catalyst for electrocatalytic water oxidation in 0.1 M phosphate buffer(pH 7.0).Cyclic voltammetry experiments indicated that the catalytic process proceed via "one-site catalysis with two-sites oxidation" mechanism in which both two metal sites store the required oxidation equivalents for water oxidation and O-O bond formation occurs by single-site water nucleophilic attack(WNA).

关键词： Water oxidation Bimetallic catalysis O-O bond formation cobalt catalyst Oxygen evolution

Highly efficient photocatalytic reduction of CO_2 and H_2O to CO and H_2 with a cobalt bipyridyl complex

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Journal of Energy Chemistry 2018年第2期27卷 502-506页

作者： Ya'nan Yao Yan Gao Lu Ye Hu Chen Licheng Sun State Key Laboratory of Fine Chemicals Institute of Artificial PhotosynthesisDUT-KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology (DUT) Department of Chemistry School of Chemical Science and EngineeringKTH Royal Institute of Technology

The development of efficient molecular catalysts for visible-light driven CO2 reduction, based on abundant materials, is necessary to meet energy demands and address environment problems. In this work,a Co（bpy）2Cl2 catalyst was developed and showed high efficiency and durability for the photocatalytic reduction of CO2 and protons. Yields of CO and H2 as high as 62.3 and 69.9 μmol were achieved and the turnover numbers（TONs） reached 6230 and 6990, respectively, under light irradiation（λ 〉 420 nm）for 4 h, indicating that the mixture gases could be a candidate as syngas. The apparent quantum yield was determined to be 2.1% for CO. Mechanistic studies revealed oxidative quenching of the photosensitizer Ru（bpy）3Cl2 by the catalyst. The photocatalytic performance, flexible synthesis and non-noble metal catalyst in our system show great promise for the practical application of Co（bpy）2Cl2 to photocatalytic reduction of CO2.

关键词： cobalt catalyst Photocatalysis CO2 reduction Oxidative quenching

Comprehensive study of nanostructured supports with high surface area for Fischer-Tropsch synthesis

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Journal of Energy Chemistry 2013年第4期22卷 573-581页

作者： Somayeh Farzad Ali Haghtalab Alimorad Rashidi Department of Chemical Engineering Tarbiat Modares University Nanotechnology Research Center Research Institute of Petroleum Industry (RIPI)

An extensive study of Fischer-Tropsch synthesis on nanostructure supports with high surface area such as nanostructure -y-alumina, single wall carbon nanotubes （SWNTs）, and the hybrid of SWNTs/nanostructure -y-alumina has been investigated. The nanostructure γ-alumina was promoted with lanthanum to obtain better performance of catalyst and 15 wt% cobalt loading was the basis of our investigation. Fischer- Tropsch synthesis was performed in a fixed bed reactor under different reaction conditions （220-240 ℃, 15-25 bar, H2/CO ratio of 2, GHSV of 900-1400） in order to study the effects of temperature, pressure and gas hourly space velocity （GHSV） changes on hydrocarbon selec- tivity and catalyst activity. The catalysts were extensively characterized by different methods including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, inductively coupled plasma （ICP）, hydrogen （H2） chemisorption and temperature-programmed reduction （TPR）. The results showed that the yield of hybrid supported catalyst （55.4%） is higher than that of nanos- tructure -y-alumina supported catalyst （55.0%） and lower than that of SWNTs supported cobalt catalyst （71.0%）. The hybrid supported catalyst showed higher reduction degree and dispersion of cobalt particles. The temperature, pressure and GHSV effects on hybrid supported catalyst were studied and results showed that higher pressure favors the chain growth and temperature increase leads to the increases in methane selec- tivity and CO conversion. Higher hydrocarbon selectivity and CO conversion showed positive relationship with increasing GHSV while lower hydrocarbon selectivity diminishes.

关键词： Fischer-Tropsch synthesis single wall carbon nanotubes nanostructure γ-Al2O3 cobalt catalyst fixed bed reactor