Catalysis in Coal and Carbon Gasification

Radović, Ljubiša R.

doi:10.1002/9783527610044.hetcat0154

Cited by 4 publications

(2 citation statements)

References 47 publications

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“…Nitrogen-bearing carbons can be prepared via postsynthetic treatment, e.g., by heating the preoxidized samples in the stream of NH 3 or HCN . Ammoxidation, a direct reaction with an ammonia−air gas mixture, supposedly proceeds at aliphatic substituents of the aromatic rings only . Ammination, in turn, consists of a reaction of ammonia with a carbon material preoxidized with HNO 3 .…”

Section: Introductionmentioning

confidence: 99%

“…Introduction of chemical groups containing nitrogen on the carbon surface enhances the specific adsorption affinity of the material. As shown by the Raman and XPS results, the basic sites in such a case are mainly associated with the nitrogen-containing defects located on the basal planes of the graphene layers . Heteroatoms, like nitrogen or oxygen atoms, generate surface polarity, conventionally measured by means of water sorption or immersion calorimetry .…”

Section: Introductionmentioning

confidence: 99%

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Investigations into the Structure of Nitrogen-Containing CMK-3 and OCM-0.75 Carbon Replicas and the Nature of Surface Functional Groups by Spectroscopic and Sorption Techniques

2009

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Mesoporous silica matrixes (SBA-15) and multilamellar vesicular (MLV) structures have been used for preparation of their nitrogen-containing carbon replicas from a pyrrole precursor. The materials have been characterized with microscopic (TEM), spectroscopic (XPS, Raman, EPR), and sorption techniques. The obtained data show that the resultant CMK-3 and OCM-0.75 replicas exhibit well-developed structures of organized graphene layers, which include surface nitrogen groups located on the graphene sheets and their edges. Influence of the siliceous template loading with FeCl 3 on the microstructure of the carbons and speciation of nitrogen has been studied. The built-in nitrogen appears in various surface functional groups that have been identified and quantified with XPS. These groups play a significant role in functionalization of the carbons toward enhanced sorption capacity. The number of paramagnetic defects has been related to the preparation stage of a carbon replica as well as to the chemical status of the heteroatom. A simple model of the surface structure of the materials, based on the spectroscopic data, has been developed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigations into the Structure of Nitrogen-Containing CMK-3 and OCM-0.75 Carbon Replicas and the Nature of Surface Functional Groups by Spectroscopic and Sorption Techniques

2009

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Catalytic Effect of Potassium Compounds in Soot Oxidation

2017

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The combustion temperatures of soot in particulate filters can be decreased to exhaust gas temperatures by using catalysts. In addition to oxidic catalysts, alkali metal salts are very effective catalysts. Although soot is one of the world's most unwanted byproducts, combustion is still not fully understood. In this study, different soot mixed internally with salt samples were produced. All salts lead to a marked, salt‐ and salt‐content‐dependent decrease of the temperature‐programmed oxidation temperatures of maximum CO + CO2 emissions (Tmax), with K2CO3 being one of the most effective catalysts that leads to a decrease of the Tmax of up to 300 °C. Structural parameters of the internally mixed soot derived by using Raman microspectroscopy, SEM, and scanning mobility particle size analysis did not change significantly; BET areas showed slight trends to lower areas with increased salt content, but no substantial correlations were observed. In contrast, a correlation of the oxidation reactivity to the number distribution of the measured actual fringe lengths by using high‐resolution transmission electron microscopy and the peak areas measured by using EPR spectroscopy was found. Salts lead to a narrowing of the actual fringe length number distributions to lower sizes and to reduced EPR peak areas. This demonstrates that the salts influence the nanostructure of the graphene planes by shortening the planes and further substantiates that soot oxidation is at least partly based on electron transfer and not only oxygen transfer. EPR spectroscopy measurements indicate that the oxidation mechanism is based on a temperature‐dependent chemical equilibrium, which depends on the K+/anion binding strength.

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An Introduction to the Combustion of Carbon Materials

Picheau

Amar

Derré

et al. 2022

Chemistry A European J

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Combustion is arguably as old as homo sapiens ability to observe and use fire. Despite the long tradition of using carbon combustion for energy production, this reaction is still not fully understood. This can be related to several facts that are intertwined and complicate the investigation, such as the large variety of possible carbon structures, the actual surface structure, porosity, the solid-gas nature of this reaction, diffusion limitation and fundamental reaction steps. In this review, a brief history of carbon combustion science is given, followed by a detailed discussion of the most important aspects of carbon combustion. Special attention is given to limitations for example diffusion. In carbon combustion, kinetic control can rarely be observed. The literature of the fundamental reaction steps actually occurring on the carbon framework is reviewed and it becomes apparent that the reaction is occurring primarily on defects on the basal plane. Thus, the reaction between oxygen and carbon may be used as an analytical tool to provide further insights into novel materials, for example synthetic carbon materials, fibres and graphene type materials. Mastering the combustion reaction in all its complexity may prove to be very valuable in the future.

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Catalysis in Coal and Carbon Gasification

Abstract: The sections in this article are Introduction Processes Catalysts Mechanisms Conclusion

Cited by 4 publications

References 47 publications

Investigations into the Structure of Nitrogen-Containing CMK-3 and OCM-0.75 Carbon Replicas and the Nature of Surface Functional Groups by Spectroscopic and Sorption Techniques

Investigations into the Structure of Nitrogen-Containing CMK-3 and OCM-0.75 Carbon Replicas and the Nature of Surface Functional Groups by Spectroscopic and Sorption Techniques

Catalytic Effect of Potassium Compounds in Soot Oxidation

An Introduction to the Combustion of Carbon Materials

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