Effect of pore size on the performance of mesoporous zirconia-supported cobalt Fischer–Tropsch catalysts

Liu, Yachun; Fang, Kegong; Chen, Jiangang; Sun, Yuhan

doi:10.1039/b614266d

Cited by 72 publications

(41 citation statements)

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“…This was similar to the literatures [1,29], which was due to the co-existence of large and small pores in bimodal support. Sun et al [4] also reported that there were different chemisorption ratios of H 2 and CO on the surface active sites for the catalysts with different pore size. The large molecules in the product could not get out of the appropriate pore, favoring to produce lighter hydrocarbons [23].…”

Section: Discussionmentioning

confidence: 99%

“…The pore size was one of the key factors for the catalyst performance, and it affected the size of cobalt oxide particles, the mass transfer of reactants and products, the re-adsorption of a-alkene, and the chemisorption ratio of H 2 and CO on the surface active sites [4]. Table 2 and Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, various materials were used as the supports of cobalt catalysts in past studies, including silica, alumina, kieselguhr, zeolite, titanium, carbon, and magnesia [3][4][5][6][7], which significantly influenced the reduction extent, the morphology, the adsorption capabilities and catalytic performance of the active phase, especially in well-dispersed catalytic systems. Among these supports, mesoporous silicas had attracted widespread attentions in FTS due to their high surface area, favoring the cobalt dispersion.…”

Section: Introductionmentioning

confidence: 99%

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Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Wang

Hou

et al. 2010

Catal Lett

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Both mono-and bi-modal Co-based FischerTropsch Synthesis (FTS) catalysts were prepared by incipient-wetness impregnation (IWI). XRD and N 2 physisorption revealed that the catalyst with a bi-modal distribution of 2.5-17 nm had the smallest size of cobalt crystal. In this case, the Raman absorbance shifted toward lower frequencies due to the size quantization effect. Furthermore, H 2 -TPR indicated a lower reducibility originated from the interaction between small crystalline cobalt and silica. Such bi-modal structure catalysts showed a better FTS performance, and particularly the bi-modal mesopores catalyst presented the lowest methane selectivity, the highest activity and the highest selectivity to C 5 -C 18 hydrocarbons, which might be due to the confinement of mesopore to the cobalt particles.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Wang

Hou

et al. 2010

Catal Lett

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Section: Introductionmentioning

confidence: 99%

“…Xiong et al 9 found that CO conversion increased and then decreased with the pore size in the range studied. Sun and co-workers 10,11 reported that the FTS catalytic performances were closely correlated to the pore sizes of the mesoporous zirconia.In general, the preparation process has a significant effect on the physical property and catalytic performance of the catalyst. The iron-based catalysts were mainly prepared by the co-precipitation, 4,9 fusion, 3 sol-gel, 12 microemulsions 13 method and so on.…”

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Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

Dong

Liu

et al. 2017

J. Braz. Chem. Soc.

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Fe 2 O 3 catalysts were prepared by co-precipitation method with the assistance of polyvinyl alcohol (PVA) for Fischer-Tropsch synthesis. Effects of PVA concentration on structure and performance of the catalyst were investigated in a fixed reactor at 230-310 °C, 1.5 MPa, 2000 h -1 , and syngas H 2 /CO = 2.0. The catalysts were characterized by N 2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), H 2 or CO temperature-programmed reduction (TPR) and H 2 temperature-programmed desorption (H 2 -TPD), Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA). It was found that there was strong interaction between Fe and PVA, which controlled the structure of the catalyst. Among the catalysts investigated, the catalyst prepared with 15 wt.% PVA exhibited better catalytic performance due to the dispersion of iron oxides and the formation of the more active phase on the catalyst. Meanwhile, this catalyst showed the high selectivity to heavy hydrocarbons and satisfactory thermal stability.Keywords: Fischer-Tropsch synthesis, iron-based catalyst, PVA concentration, structure, stability IntroductionFischer-Tropsch synthesis (FTS), an efficient technology to convert syngas into liquid fuels and chemicals, has attracted great interest due to the shrinking of the petroleum resource in the past decades.1 Iron-based catalysts have attracted considerable focus, thanks to their low cost, high activity and excellent water-gas-shift reactivity, which match coal gasification with low H 2 /CO ratio. 2 Remarkably, three principal challenges are posed for iron-based FTS catalyst: activity, selectivity and stability. 3 It is well known that the activity, selectivity and stability of FTS catalysts rely strongly on the texture and surface properties of the resultant catalysts. 4 Most of all, the pore size of catalyst is one of the key factors, which has significant effect on the mass transfer of reactants and products, 5 the re-adsorption of the α-alkene, and the chemisorption ratio of H 2 on the surface active sites exposed. 6 Therefore, these factors are vital for the performance of catalyst in the FTS. For instance, smaller pore size of catalyst can afford high Brunauer, Emmett and Teller (BET) surface area and dispersion of the catalyst. However, diffusion effects of products were limited, resulting in light hydrocarbons as the main product for excessive hydrogenation. In contrast, the larger pore size of catalyst can facilitate the diffusion of products, and thus products of heavy hydrocarbons are obtained.7 Tao et al. 8 proposed that the FTS catalytic activity and product selectivity rely strongly on the pore size distribution of the catalysts. Xiong et al. 9 found that CO conversion increased and then decreased with the pore size in the range studied. Sun and co-workers 10,11 reported that the FTS catalytic performances were closely correlated to the pore sizes of the mesoporous zirconia.In general, the preparation process has a significant e...

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Recent Advances in Copper‐Catalyzed Functionalization of Unactivated C(sp³)−H Bonds

et al. 2022

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C(sp 3 )À H functionalization is a core part of organic chemistry because of the presence of C(sp 3 )À H bonds in various organic molecules. However, since most C(sp 3 )À H bonds are non-reactive, their functionalization is an uphill task. Standard methods of functionalization employ prefunctionalized reactants, expensive organometallic reagents, strong acids or bases and similar other harsh reaction conditions. These methods eventually affect the reaction and prevent it from yielding optimum results. Transition metalbased catalysts like Pd, Rh and Ru provide a direct functionalization route without unwanted pre-functionalization steps. These catalysts furnish superior results under mild reaction conditions. But, their expense, toxicity and low natural abundance prevent them from achieving ideality. Therefore, 3d transition metal catalysts like Mn, Fe, Co, Ni and Cu catalysts have gained significance as an alternative for conventional transition metal catalysts due to their high natural abundance, low toxicity and affordability. Copperbased catalysts are particularly important owing to the wide range of oxidation states of copper and the facile tunability of their catalytic properties. Hence, an immense amount of research is being conducted on the catalytic activity of copper for C(sp 3 )À H functionalization. This review aims to provide a detailed overview of some recent reports on C(sp 3 )À H functionalization using catalytic systems based on copper.

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Effect of pore size on the performance of mesoporous zirconia-supported cobalt Fischer–Tropsch catalysts

Cited by 72 publications

References 35 publications

Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

Recent Advances in Copper‐Catalyzed Functionalization of Unactivated C(sp³)−H Bonds

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Effect of pore size on the performance of mesoporous zirconia-supported cobalt Fischer–Tropsch catalysts

Cited by 72 publications

References 35 publications

Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Textural Structure of Co-based Catalysts and their Performance for Fischer–Tropsch Synthesis

Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

Recent Advances in Copper‐Catalyzed Functionalization of Unactivated C(sp3)−H Bonds

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Recent Advances in Copper‐Catalyzed Functionalization of Unactivated C(sp³)−H Bonds