The catalysis of the oxidation of carbon

Long, Frank; Sykes, Keith

doi:10.1051/jcp/1950470361

Cited by 69 publications

(32 citation statements)

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“…[36][37][38][39] Turkdogan and Vinters [39] have shown that the rate of oxidation of graphite impregnated with iron in CO 2 -CO mixtures increases by several orders of magnitude over the rate for graphite alone. For charcoal (with 3.5 pct ash, mainly Na 2 O, K 2 O, Fe 2 O 3 , Al 2 O, and SiO 2 ) gasification by H 2 O, Long and Sykes [40] obtained an activation energy of around 230 kJ/mol, but, after the extraction of impurities, the activation energy was estimated to be about 347 kJ/mol. Fruehan [5] hypothesizes that such a dramatic catalytic effect takes place when the catalyst is impregnated into the carbon, but if there is just simple contact with the carbon, the change of the rate should not be significant.…”

Section: B Local Rates Of Reduction and Gasificationmentioning

confidence: 99%

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Estimation and modeling of parameters for direct reduction in iron ore/coal composites: Part II. Kinetic parameters

Donskoi

McElwain

Wibberley

2003

Metall Mater Trans B

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The published approaches to the mathematical modeling of rates of reduction, of coal gasification, and of devolatilization of coal in iron/ore coal composites are reviewed and critically analyzed. The effect of different parameters on the overall process is discussed. The concepts of a local rate of reduction and gasification and an integrated rate of reduction are introduced, and the rate-controlling steps in each are reviewed. Current approaches to modeling coal pyrolysis are also described. This review, with the estimates, data, and analysis related to modeling rates of reduction, gasification, and pyrolysis, should prove useful to researchers developing models of coalbased iron ore reduction and related processes.

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Section: B Local Rates Of Reduction and Gasificationmentioning

confidence: 99%

“…Taking into account that many studies (Table I) have shown the validity of an Arrhenius dependence during the reduction process, initially simple expressions for local rates of reduction and gasification such as [40] [41] …”

Section: B Local Rates Of Reduction and Gasificationmentioning

confidence: 99%

Estimation and modeling of parameters for direct reduction in iron ore/coal composites: Part II. Kinetic parameters

Donskoi

McElwain

Wibberley

2003

Metall Mater Trans B

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“…However, when knowledge of the essential details of electron transfer [35,36] is required (or is at least desirable), current understanding of the surface chemistry of graphene is not sufficient. In particular, the synergistic effects of iron and nitrogen on the carbon surface -reported almost a century ago [37] -are still waiting for a satisfactory explanation (as well as for some practical applications!…”

Section: Introductionmentioning

confidence: 99%

Pyrolyzed phthalocyanines as surrogate carbon catalysts: Initial insights into oxygen-transfer mechanisms

Vallejos-Burgos

Utsumi

Hattori

et al. 2012

Fuel

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a b s t r a c tDeposited and heat-treated phthalocyanines are promising electrocatalysts for replacing platinum in the oxygen reduction reaction (ORR), the most important process in energy conversion systems such as fuel cells; and yet its key mechanistic features are not well understood. To optimize their use, it is necessary to understand their behavior in the absence of an electric field. In the pursuit of this goal, we pyrolyzed metal-free, cobalt and copper phthalocyanines between 550 and 1000°C and studied their structural and chemical changes by elemental analysis, N 2 and CO 2 adsorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray analysis fine structure (XAFS) and X-ray photoelectron spectroscopy (XPS). Their catalytic activity was assessed by non-isothermal O 2 gasification and NO reduction reactions. A comparison of these results with their other properties allowed us to reach the following conclusions: (i) the loss of reactivity of metal-free phthalocyanine with heat treatment is attributed to its structural annealing and heteroatom loss, with the porosity changes having no effect; (ii) for metal phthalocyanines at intermediate heat treatment temperatures, the optimum in reactivity correlates with the micropore surface area and the presence of metal particles, with no influence of nitrogen content; (iii) the coordination metal increases phthalocyanine thermal stability in an inert atmosphere, but in an oxidizing atmosphere it acts as a gasification catalyst even below decomposition temperatures. The implications of these findings for catalytic oxygen-transfer mechanisms are discussed.

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“…So it can be understood as having a mechanistic meaning. Table 5 compares the success in explaining the observed kinetic behavior, assuming the C dissolution-bulk diffusion-external surface reaction mechanism or any of the 12 mechanisms [1,3,9,[72][73][74][75][76][77][78][79][80] listed by Moulijn and Kapteijn in 1986 [43] and recalled by Li et al recently in this journal [8]. One of the mechanisms has frequent citations, particularly in recent years [74].…”

Section: Solid-state Phases Alternating and Steady State (Linear) Kinmentioning

confidence: 99%

“…Important reviews are available [1][2][3][4][5][6][7][8]. The two general mechanisms first proposed for catalytic carbon gasification were electron-transfer and oxygen transfer, the latter initially proposed for the O 2 reaction [9][10][11]. Both mechanisms fail to explain the kinetic behavior.…”

Section: Introductionmentioning

confidence: 99%