Kinetics of Nickel Carbonyl Formation

Goldberger, W. M.; Othmer, Donald F.

doi:10.1021/i260007a006

Cited by 32 publications

(17 citation statements)

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“…This corresponds to a Ni/Cu ratio of ~4.48 and ~4.56 for the fresh and spent catalysts, respectively, which clearly indicates that the catalyst experiences no loss of Ni. This is consistent with a report on the kinetics of nickel carbonyl formation [38]. Indeed, the authors of this report concluded that the highly exothermic reaction that forms nickel carbonyl reaches a maximum rate at ~75 °C, after which nickel carbonyl formation decreases to reach negligible levels by 150 °C irrespective of the pressures (partial CO, H2, or total pressure) employed.…”

Section: Catalyst Characterizationsupporting

confidence: 93%

Continuous Catalytic Deoxygenation of Waste Free Fatty Acid-Based Feeds to Fuel-Like Hydrocarbons Over a Supported Ni-Cu Catalyst

et al. 2019

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While commercial hydrodeoxygenation (HDO) processes convert fats, oils, and grease (FOG) to fuel-like hydrocarbons, alternative processes based on decarboxylation/decarbonylation (deCOx) continue to attract interest. In this contribution, the activity of 20% Ni-5% Cu/Al2O3 in the deCOx of waste free fatty acid (FFA)-based feeds—including brown grease (BG) and an FFA feed obtained by steam stripping a biodiesel feedstock—was investigated, along with the structure-activity relationships responsible for Ni promotion by Cu and the structural evolution of catalysts during use and regeneration. In eight-hour experiments, near quantitative conversion of the aforementioned feeds to diesel-like hydrocarbons was achieved. Moreover, yields of diesel-like hydrocarbons in excess of 80% were obtained at all reaction times during a BG upgrading experiment lasting 100 h, after which the catalyst was successfully regenerated in situ and found to display improved performance during a second 100 h cycle. Insights into this improved performance were obtained through characterization of the fresh and spent catalyst, which indicated that metal particle sintering, alloying of Ni with Cu, and particle enrichment with Cu occur during reaction and/or catalyst regeneration.

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Section: Catalyst Characterizationsupporting

confidence: 93%

Continuous Catalytic Deoxygenation of Waste Free Fatty Acid-Based Feeds to Fuel-Like Hydrocarbons Over a Supported Ni-Cu Catalyst

et al. 2019

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“…during the production of the gas). [16][17][18] Using Spacetime soware 19 the data proles from the gas supply system, QMS and nanoreactor temperature were synchronised and analysed.…”

Section: Gas Supply System and Residual Gas Analysismentioning

confidence: 99%

In situ TEM observation of the Boudouard reaction: multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure

et al. 2017

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Using a MEMS nanoreactor in combination with a specially designed in situ Transmission Electron Microscope (TEM) holder and gas supply system, we imaged the formation of multiple layers of graphene encapsulating a cobalt nanoparticle, at 1 bar CO : N (1 : 1) and 500 °C. The cobalt nanoparticle was imaged live in a TEM during the Boudouard reaction. The in situ/operando TEM studies give insight into the behaviour of the catalyst at the nanometer-scale, under industrially relevant conditions. When switching from Fischer-Tropsch syngas conditions (CO : H : N 1 : 2 : 3 at 1 bar) to CO-rich conditions (CO : N 1 : 1 at 1 bar), we observed the formation of multi-layered graphene on Co nanoparticles at 500 °C. Due to the high temperature, the surface of the Co nanoparticles facilitated the Boudouard reaction, causing CO dissociation and the formation of layers of graphene. After the formation of the first patches of graphene at the surface of the nanoparticle, more and more layers grew over the course of about 40 minutes. In its final state, around 10 layers of carbon capped the nanoparticle. During this process, the carbon shell caused mechanical stress in the nanoparticle, inducing permanent deformation.

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“…[22] In this process deactivation can occur by deposition of carbon on the active metal surface and by Ostwald ripening through the formation of [Ni(CO) 4 ] species. [23][24][25][26][27] The influence of the nickel particle size and spatial distribution on the nanoparticle stability remains poorly understood, which hampers the optimization of these catalysts.…”

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confidence: 99%

Nanoparticle Growth in Supported Nickel Catalysts during Methanation Reaction—Larger is Better

Munnik¹,

Velthoen²,

Jongh³

et al. 2014

Angew Chem Int Ed

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A major cause of supported metal catalyst deactivation is particle growth by Ostwald ripening. Nickel catalysts, used in the methanation reaction, may suffer greatly from this through the formation of [Ni(CO)4 ]. By analyzing catalysts with various particle sizes and spatial distributions, the interparticle distance was found to have little effect on the stability, because formation and decomposition of nickel carbonyl rather than diffusion was rate limiting. Small particles (3-4 nm) were found to grow very large (20-200 nm), involving local destruction of the support, which was detrimental to the catalyst stability. However, medium sized particles (8 nm) remained confined by the pores of the support displaying enhanced stability, and an activity 3 times higher than initially small particles after 150 h. Physical modeling suggests that the higher [Ni(CO)4 ] supersaturation in catalysts with smaller particles enabled them to overcome the mechanical resistance of the support. Understanding the interplay of particle size and support properties related to the stability of nanoparticles offers the prospect of novel strategies to develop more stable nanostructured materials, also for applications beyond catalysis.

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Kinetics of Nickel Carbonyl Formation

Cited by 32 publications

References 0 publications

Continuous Catalytic Deoxygenation of Waste Free Fatty Acid-Based Feeds to Fuel-Like Hydrocarbons Over a Supported Ni-Cu Catalyst

Continuous Catalytic Deoxygenation of Waste Free Fatty Acid-Based Feeds to Fuel-Like Hydrocarbons Over a Supported Ni-Cu Catalyst

In situ TEM observation of the Boudouard reaction: multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure

Nanoparticle Growth in Supported Nickel Catalysts during Methanation Reaction—Larger is Better

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