Role of CO in the Water-Induced Formation of Cobalt Oxide in a High Conversion Fischer–Tropsch Environment

ACS Catalysis ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 3985-3989 ◽  
Author(s):  
Moritz Wolf ◽  
Bridget K. Mutuma ◽  
Neil J. Coville ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Cobalt Oxide ◽  
High Conversion ◽  
Fischer Tropsch

scholarly journals Things go better with coke: the beneficial role of carbonaceous deposits in heterogeneous catalysis

2016 ◽  
Vol 6 (2) ◽  
pp. 363-378 ◽  
Author(s):  
C. H. Collett ◽  
J. McGregor
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Catalytic Performance ◽  
Fischer Tropsch ◽  
Carbonaceous Deposits ◽  
Beneficial Role ◽  
Catalytic Processes

Carbonaceous deposits on heterogeneous catalysts are traditionally associated with catalyst deactivation. However, they can play a beneficial role in many catalytic processes, e.g. dehydrogenation, hydrogenation, alkylation, isomerisation, Fischer–Tropsch, MTO etc. This review highlights the role and mechanism by which coke deposits can enhance catalytic performance.

Size dependent stability of cobalt nanoparticles on silica under high conversion Fischer–Tropsch environment

2017 ◽  
Vol 197 ◽  
pp. 243-268 ◽  
Author(s):  
Moritz Wolf ◽  
Hendrik Kotzé ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Type Species ◽  
Tropsch Synthesis ◽  
High Conversion ◽  
Metallic Surface ◽  
Metallic State ◽  
Direct Oxidation ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Metal Support ◽  
Presence And Absence

Highly monodisperse cobalt crystallites, supported on Stöber silica spheres, as model catalysts for the Fischer–Tropsch synthesis were exposed to simulated high conversion environments in the presence and absence of CO utilising an in house developedin situmagnetometer. The catalyst comprising the smallest crystallites in the metallic state (average diameter of 3.2 nm) experienced pronounced oxidation whilst the ratio of H2O to H2was increased stepwise to simulate CO conversions from 26% up to complete conversion. Direct exposure of this freshly reduced catalyst to a high conversion Fischer–Tropsch environment resulted in almost spontaneous oxidation of 40% of the metallic cobalt. In contrast, a model catalyst with cobalt crystallites of 5.3 nm only oxidised to a small extent even when exposed to a simulated conversion of over 99%. The largest cobalt crystallites were rather stable and only experienced measurable oxidation when subjected to H2O in the absence of H2. This size dependency of the stability is in qualitative accordance with reported thermodynamic calculations. However, the cobalt crystallites showed an unexpected low susceptibility to oxidation,i.e.only relatively high ratios of H2O to H2partial pressure caused oxidation. Similar experiments in the presence of CO revealed the significance of the actual Fischer–Tropsch synthesis on the metallic surface as the dissociation of CO, an elementary step in the Fischer–Tropsch mechanism, was shown to be a prerequisite for oxidation. Direct oxidation of cobalt to CoO by H2O seems to be kinetically hindered. Thus, H2O may only be capable of indirect oxidation,i.e.high concentrations prevent the removal of adsorbed oxygen species on the cobalt surface leading to oxidation. However, a spontaneous direct oxidation of cobalt at the interface between the support and the crystallites by H2O forming presumably cobalt silicate type species was observed in the presence and absence of CO. The formation of these metal–support compounds is in accordance with conducted thermodynamic predictions. None of the extreme Fischer–Tropsch conditions initiated hydrothermal sintering. Seemingly, the formation of metal–support compounds stabilised the metallic crystallites and/or higher partial pressures of CO are required to increase the concentration of mobile, cobalt oxide-type species on the metallic surface.

Support Effect of the Fe/BN Catalyst on Fischer–Tropsch Performances: Role of the Surface B–O Defect

2018 ◽  
Vol 57 (8) ◽  
pp. 2805-2810 ◽  
Author(s):  
Jianghong Wu ◽  
Liancheng Wang ◽  
Xi Yang ◽  
Baoliang Lv ◽  
Jiangang Chen
Keyword(s):  
Support Effect ◽  
Fischer Tropsch

Role of oxygen flow rate on the structure and stoichiometry of cobalt oxide films deposited by reactive sputtering

2022 ◽  
Vol 40 (1) ◽  
pp. 013405
Author(s):  
Nilton Francelosi A. Neto ◽  
Cristiane Stegemann ◽  
Lucas J. Affonço ◽  
Douglas M. G. Leite ◽  
José H. D. da Silva
Keyword(s):  
Cobalt Oxide ◽  
Flow Rate ◽  
Oxide Films ◽  
Reactive Sputtering ◽  
Oxygen Flow Rate ◽  
Oxygen Flow

Role of mesopores in Co/ZSM-5 for the direct synthesis of liquid fuel by Fischer–Tropsch synthesis

2018 ◽  
Vol 8 (24) ◽  
pp. 6346-6359 ◽  
Author(s):  
Ji-Eun Min ◽  
Sungtak Kim ◽  
Geunjae Kwak ◽  
Yong Tae Kim ◽  
Seung Ju Han ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Pore Structure ◽  
Liquid Fuel ◽  
Direct Synthesis ◽  
Reaction System ◽  
Complex Reaction ◽  
Fischer Tropsch ◽  
Solid Catalysts ◽  
The Impact

In a complex reaction system, in which gas, liquid, and solid catalysts work together, understanding the impact of mass transfer that varies with the catalyst pore structure is very challenging but also essential to designing selective catalysts.

Water-Induced Formation of Cobalt-Support Compounds under Simulated High Conversion Fischer–Tropsch Environment

ACS Catalysis ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 4902-4918 ◽  
Author(s):  
Moritz Wolf ◽  
Emma K. Gibson ◽  
Ezra J. Olivier ◽  
Jan H. Neethling ◽  
C. Richard A. Catlow ◽  
...  
Keyword(s):  
High Conversion ◽  
Fischer Tropsch

scholarly journals THE PROTECTIVE ROLE OF OMEGA-3 AGAINST GENOTOXICITY AND REPRODUCTIVE TOXICITY OF COBALT OXIDE NANOPARTICLES ACUTE TREATMENT IN MALE MICE

2018 ◽  
Vol 11 (5) ◽  
pp. 423
Author(s):  
Nahed A Hussien ◽  
Hanan R. H. Mohamed
Keyword(s):  
Cobalt Oxide ◽  
Negative Control Group ◽  
Protective Role ◽  
Negative Control ◽  
Control Group ◽  
Omega 3 ◽  
Genotoxic Potential ◽  
Polychromatic Erythrocytes

Objective: Cobalt nanoparticles (NPs), especially cobalt oxide NPs (Co3O4 NPs) are attracting unique shaped NPs that are used in different biomedical applications and medicine. Different in vitro studies report their toxic and carcinogenic effect but limited in vivo studies were present on its genotoxic potential. The present study was aimed to evaluate the genotoxic potential of Co3O4 NPs on bone marrow cells and sperms and the protective role of omega-3 in male albino mice.Methods: Animals were segregated into four groups that were orally treated for 3 consecutive days, Group 1: Negative control; Group 2: Omega-3 (250 mg/kg); Group 3: Co3O4 NPs (20 mg/kg); and Group 4: Combined group (250 mg/kg Omega-3 and Co3O4 NPs 20 mg/kg).Results: The present results show that Co3O4 NPs administration significantly increased number of micronucleated polychromatic erythrocytes (PCEs)/1000 PCEs, sperm abnormalities, and DNA damage, significantly decreased sperm motility and concentration in comparison to negative control group. However, Omega-3 administration in the combined group modulates the genotoxic potential of Co3O4 NPs in comparison to Co3O4 NPs group.Conclusion: The present study reports the genotoxic potential of Co3O4 NPs in vivo and assesses the protective role of Omega-3 administration due to its antioxidant effect.

Supported Fe/MnOx catalyst with Ag doping for remarkably enhanced catalytic activity in Fischer–Tropsch synthesis

2018 ◽  
Vol 8 (7) ◽  
pp. 1953-1970 ◽  
Author(s):  
Yuebing Xu ◽  
Xinli Jia ◽  
Xiaohao Liu
Keyword(s):  
Catalytic Activity ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Ag Doping

The role of Ag in the promotion of the FTS performance and the evolutions of structure and phase over the Fe/MnOx catalyst has been clearly elucidated.

Sign in / Sign up

Export Citation Format

Share Document