scholarly journals Effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts supported on carbon nanotubes in Fischer–Tropsch synthesis

2019 ◽  
Vol 44 (4) ◽  
pp. 316-323 ◽  
Author(s):  
Ali Nakhaei Pour ◽  
Mohammadreza Housaindokht
Keyword(s):  
Catalytic Activity ◽  
Cobalt Catalysts ◽  
Crystal Phase ◽  
Microemulsion System ◽  
Face Centered Cubic ◽  
Metallic Cobalt ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Hexagonal Close Packed ◽  
Face Centered

The effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts in the Fischer–Tropsch synthesis were investigated in a continuous spinning basket reactor. The cobalt catalysts were prepared by impregnation of the cobalt active phase in a microemulsion system on multiwall carbon nanotube supports. A series of cobalt catalysts with different Co particle sizes was prepared by variation of the water-to-surfactant molar ratio from 2 to 12 in the microemulsion system. The X-ray diffraction results validate a complex composition of cobalt phases containing cobalt oxides and metallic cobalt with hexagonal close-packed and face-centered cubic phases. The results show that larger cobalt particles exhibit more face-centered cubic and less hexagonal close-packed metallic cobalt. The experimental results show that the catalysts with higher fractions of hexagonal close-packed phase exhibited higher conversion in the Fischer–Tropsch reaction.

Enhanced catalytic activity of cobalt catalysts for Fischer–Tropsch synthesis via carburization and hydrogenation and its application to regeneration

2016 ◽  
Vol 6 (12) ◽  
pp. 4594-4600 ◽  
Author(s):  
Geunjae Kwak ◽  
Du-Eil Kim ◽  
Yong Tae Kim ◽  
Hae-Gu Park ◽  
Seok Chang Kang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Material ◽  
Catalytic Performance ◽  
Tropsch Synthesis ◽  
Cobalt Catalysts ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Cobalt Carbide ◽  
Catalytically Active

In Fischer–Tropsch synthesis (FTS), cobalt carbide (Co2C) is not a catalytically active material, but rather an undesired cobalt phase associated with low catalytic performance.

Preparation of Co3Ni Film Composed of Nanosheets and their Catalytic Activity in Hydrogen Generation from Sodium Borohydride Solution

2013 ◽  
Vol 860-863 ◽  
pp. 822-825
Author(s):  
Jin Yun Liao ◽  
Hao Li ◽  
Xi Bin Zhang
Keyword(s):  
Catalytic Activity ◽  
High Performance ◽  
Hydrogen Generation ◽  
Deposition Process ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Original Activity ◽  
Hexagonal Close Packed ◽  
Face Centered

In this study, aiming to obtain high performance nanocatalysts for NaBH4 hydrolysis, Co3Ni film composed of nanosheets with a mean thickness of 10 nm was fabricated by a magnetic field induced deposition process. X-ray diffraction analysis indicated that the as-prepared Co3Ni film is presented in both face-centered cubic phase and hexagonal close-packed phase. The nanostructured Co3Ni film catalyst showed good catalytic activity in the hydrolysis of NaBH4 and the rate constant was 5.77 mL·min-1. It was revealed that Co3Ni film catalysts didnt lose their catalytic original activity essentially after 10 cycles, which exhibited much improved reusability and stability compared with with recently reported nanocatalysts.

The catalytic activity of microporous and mesoporous NiCoBeta zeolite catalysts in Fischer–Tropsch synthesis

2021 ◽  
Vol 47 (1) ◽  
pp. 397-418
Author(s):  
Karolina A. Chalupka ◽  
Renata Sadek ◽  
Lukasz Szkudlarek ◽  
Pawel Mierczynski ◽  
Waldemar Maniukiewicz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Tropsch Synthesis ◽  
Zeolite Catalysts ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

scholarly journals Stability and equation of state of face-centered cubic and hexagonal close packed phases of argon under pressure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnès Dewaele ◽  
Angelika D. Rosa ◽  
Nicolas Guignot ◽  
Denis Andrault ◽  
João Elias F. S. Rodrigues ◽  
...  
Keyword(s):  
Equation Of State ◽  
Single Crystal ◽  
Single Crystal Sample ◽  
Moderate Pressure ◽  
Face Centered Cubic ◽  
Experimental Conditions ◽  
Crystal Sample ◽  
Hexagonal Close Packed ◽  
Face Centered ◽  
Fcc Phase

AbstractThe compression of argon is measured between 10 K and 296 K up to 20 GPa and and up to 114 GPa at 296 K in diamond anvil cells. Three samples conditioning are used: (1) single crystal sample directly compressed between the anvils, (2) powder sample directly compressed between the anvils, (3) single crystal sample compressed in a pressure medium. A partial transformation of the face-centered cubic (fcc) phase to a hexagonal close-packed (hcp) structure is observed above 4.2–13 GPa. Hcp phase forms through stacking faults in fcc-Ar and its amount depends on pressurizing conditions and starting fcc-Ar microstructure. The quasi-hydrostatic equation of state of the fcc phase is well described by a quasi-harmonic Mie–Grüneisen–Debye formalism, with the following 0 K parameters for Rydberg-Vinet equation: $$V_0$$ V 0 = 38.0 Å$$^3$$ 3 /at, $$K_0$$ K 0 = 2.65 GPa, $$K'_0$$ K 0 ′ = 7.423. Under the current experimental conditions, non-hydrostaticity affects measured P–V points mostly at moderate pressure ($$\le$$ ≤ 20 GPa).

scholarly journals Fischer–Tropsch Synthesis for Light Olefins from Syngas: A Review of Catalyst Development

Reactions ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 227-257
Author(s):  
Arash Yahyazadeh ◽  
Ajay K. Dalai ◽  
Wenping Ma ◽  
Lifeng Zhang
Keyword(s):  
Pore Size ◽  
Crystal Size ◽  
Tropsch Synthesis ◽  
Light Olefins ◽  
Face Centered Cubic ◽  
Fischer Tropsch ◽  
Light Olefin ◽  
Structure Transition ◽  
Fischer Tropsch Synthesis ◽  
Olefin Selectivity

Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA).

Improvement of C–C Coupling Using SiC as a Support of Cobalt Catalysts in Fischer Tropsch Synthesis

2021 ◽  
Author(s):  
Gisele Westphalen ◽  
Maria A. S. Baldanza ◽  
Antônio José de Almeida ◽  
Vera Maria Martins Salim ◽  
Mônica Antunes Pereira da Silva ◽  
...  
Keyword(s):  
Tropsch Synthesis ◽  
Cobalt Catalysts ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

scholarly journals Microstructure Refinement by Low-Temperature Ausforming in an Fe-Based Metastable High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 742
Author(s):  
Motomichi Koyama ◽  
Takeaki Gondo ◽  
Kaneaki Tsuzaki
Keyword(s):  
Low Temperature ◽  
Plastic Anisotropy ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Microstructure Refinement ◽  
Hexagonal Close Packed ◽  
Solution Treated Condition ◽  
Solution Treated ◽  
Face Centered

The effects of ausforming in an Fe30Mn10Cr10Co high-entropy alloy on the microstructure, hardness, and plastic anisotropy were investigated. The alloy showed a dual-phase microstructure consisting of face-centered cubic (FCC) austenite and hexagonal close-packed (HCP) martensite in the as-solution-treated condition, and the finish temperature for the reverse transformation was below 200 °C. Therefore, low-temperature ausforming at 200 °C was achieved, which resulted in microstructure refinement and significantly increased the hardness. Furthermore, plasticity anisotropy, a common problem in HCP structures, was suppressed by the ausforming treatment. This, in turn, reduced the scatter of the hardness.

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