Nickel and Fischer-Tropsch Synthesis

Enger, Bjørn Christian; Holmén, Anders

doi:10.1080/01614940.2012.670088

Cited by 122 publications

(87 citation statements)

References 117 publications

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“…These small particle sizes are classically not even believed to be capable of activating π -bonds 21,22 . The maximum current model in (cobalt) face-centred-cubic nanoparticles gives a fraction of approximately 1% of these active B 5 sites for 1.2 nm particles 44 . This discrepancy gives us some important new insights into the likely restructuring effects exhibited by catalysts with such small Ni particle sizes, as we prove that the atomic coordinations that can cleave π -bonds are present (albeit in small quantities) under working conditions.…”

Section: Nature Catalysismentioning

confidence: 99%

Unravelling structure sensitivity in CO2 hydrogenation over nickel

et al. 2018

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T he reduction of CO 2 emissions into the Earth's atmosphere is gaining legislative importance in view of its impact on the climate [1][2][3][4][5] . Reduction of the harmful effect of these emissions through reclamation of CO 2 is made attractive because CO 2 can be a zero-or even negative-cost carbon feedstock 6,7 . The conversion of renewably produced hydrogen and CO 2 into methane, or synthetic natural gas, over Ni is a solution that combines the potential to reduce CO 2 emissions with a direct answer to the temporal mismatch in renewable electricity production capacity and demand [8][9][10][11][12][13][14][15][16][17] . Chemical energy storage in the form of hydrogen production by electrolysis is a relatively mature technology; however, the required costly infrastructure, and inefficiencies in distribution and storage deem it inconvenient for large-scale application in the near future. Point-source CO 2 hydrogenation to methane represents an alternative approach with higher energy density. Furthermore, methane is more easily liquefied and can be stored safely in large quantities through infrastructures that already exist 18,19 . Power-to-gas (in this case methane) is thus actively considered as being capable of balancing electric grid stability, which will allow us to increase the renewable energy supply 20 .The search for fossil fuel alternatives, and application of a process such as that described above can arguably be achieved only with the help of advances in catalysis and the closely related field of nanomaterials. Continuous efforts in both fields have allowed us to make increasingly smaller and catalytically more active (metal) particles. However, it is already known that making progressively smaller supported catalyst particles does not necessarily linearly correspond to higher catalytic activity [21][22][23] . This phenomenon, where not all atoms in a supported metal catalyst have the same activity, is called structure sensitivity and is often attributed to the distinctly different chemistries on different lattice planes for π -bond activation in CO 2 , or σ -bond activation in, for example H 2 dissociation and C-H propagation 21,24 . The availability of stepped (less coordinated) versus terrace (more coordinated) sites on the surface of supported catalyst nanoparticles obviously changes with particle size, and atomic geometries become particularly interesting below 2 nm where, for example, π -bond activation is believed to not be able to occur 21 . While particle-size effects have been extensively studied for CO hydrogenation over Co 23,25 , the understanding of such structure sensitivity effects for these critical smaller metal particle sizes is lacking as sub-2-nm particles prove difficult to synthesize for first-row transition metals (Co, Fe and Ni). However, a particle-size effect for CO 2 hydrogenation is much less well established 26 .Here, we used a unique set of SiO 2 -supported Ni nanoparticles with diameters ranging from 1 to 7 nm in size, and show not only the existence of a distinct pa...

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Section: Nature Catalysismentioning

confidence: 99%

Unravelling structure sensitivity in CO2 hydrogenation over nickel

et al. 2018

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“…Fischer-Tropsch synthesis (FTS) is one of the most technologically feasible processes for producing transportation fuels from a range of feed stocks such as natural gas, coal, municipal solid waste, and biomass (Enger and Holmen, 2012;. Efforts to synthesize hydrocarbons through the catalytic hydrogenation of carbon monoxide (CO) date back to 1902, when Sabatier and Senderens synthesized hydrocarbons from CO and hydrogen (H 2 ) (Calderone et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Direct syngas hydrogenation over a Co–Ni bimetallic catalyst: Process parameter optimization

Ramasamy

Gray

Job

et al. 2015

Chemical Engineering Science

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Low metal loading Co-Ni bimetallic catalyst for the CO hydrogenation/FTS. Very high olefin to paraffin ratio generated. The highest olefin to paraffin ratio of 8 was observed for C 3 hydrocarbon. Demonstrated dual bed configuration to convert oxygenates. a b s t r a c tThe syngas hydrogenation activity of the Co-Ni bimetallic catalyst containing total metal loading less than 10 wt% was prepared via a wet impregnation method and was studied with respect to the reaction temperature and the catalyst composition. Among the hydrocarbons generated, small olefinic compounds between C 2 and C 7 (up to 40%) were the highest in the product mixture. The olefin to paraffin ratio for C 3 hydrocarbon is around 8. For all variables tested, the product distribution contains up to 10% oxygenates along with the hydrocarbon compounds. An acidic alumina containing reactor was added followed by the Co-Ni containing reactor to demonstrate the deoxygenation of oxygenates generated from the FTS process to improve the small olefinic fraction and the overall carbon yield to the valuable products.

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“…Nevertheless, the stability of nickelbased catalysts is threatened by multiple causes of deactivation occurring at different operating conditions. At low temperatures (473-573 K) and high CO partial pressures, there is a high risk for nickel carbonyl formation which results in the loss of nickel and/or nickel particle sintering [23,24]. At moderately high temperatures (up to 723 K) there is a potential for formation of polymeric carbon, also known as "gum" formation [3,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%