Catalytic activity of carbon catalysts for the reaction of NOx with NH3

Jüntgen, H.; Richter, Ekkehard; Kühl, Helmut

doi:10.1016/0016-2361(88)90149-4

Cited by 29 publications

(7 citation statements)

References 4 publications

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“…This function may overlap with the widespread application of high surface area carbons ad sorbents for selective chemisorption processes which is no considered here. The application of carbon as a catalyst in its own right was reviewed several times [211,212,213]. All applications are based on the simultaneous action of two functions.…”

Section: Carbon As Catalystmentioning

confidence: 99%

Carbons

Schlögl

2008

Handbook of Heterogeneous Catalysis

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The element carbon plays a multiple role in heterogeneous catalysis. In homogeneous catalysis it occurs of course as the most prominent constituent of ligand systems and will be treated as such there. Carbon-containing molecules are, in most catalytic applications, the substrates of the process under consideration. Deposits and polymers of carbon often occur as poisons on catalysts. Carbon deposition is the most severe problem in certain zeolite applications. In hydrogenation reactions carbon deposits are thought to act as modifiers for the activity of the catalyst and to provide selectivity by controlling the hydrogenationdehydrogenation activity of the metal part of the catalyst. Carbon deposits are even thought to constitute part of the active sites in some cases. Carbon is a prominent catalyst support material as it allows the anchoring of metal particles on a substrate which does not exhibit solid acid-base properties. Carbon is finally a catalyst in its own right allowing the activation of oxygen and chlorine for selective oxidation, chlorination and de-chlorination reactions. These multiple roles of the element carbon are in parallel with a complex structural chemistry giving rise to families of chemically vastly different modifications of the element. It is a special characteristic of carbon chemistry that many of these modifications cannot be obtained as phase-pure materials. This limits the exact knowledge of physical and chemical properties to a few archetype modifications, namely graphite and diamond. The reason for this poor definition of materials is found in the process of its formation. This is comprised of difficult to control polymerisation reactions. Such reactions will occur also in catalytic reactions with small organic molecules. The nature of carbon deposits will therefore reflect all the complexity of the bulk carbon materials. It is one aim of this article to describe the structural and chemical complexity of "carbon" or "soot" in order to provide an understanding of the frequently observed complexity of the chemical reactivity (e.g. in re-activation processes aiming at an oxidative removal of deposits). The surface chemistry of carbon which determines its interfacial properties is a rich field as a wide variety of surface functional groups are known to exist on carbon. The by far most important family of surface functional groups are those involving oxygen. Other prominent heteroatoms on the surface are hydrogen and nitrogen. This article focusses on the description and characterisation of oxygen surface functional groups. In the final section, selected case studies of carbon chemistry in catalysis will be discussed in order to illustrate characteristic properties of carbon materials as wanted or unwanted components in catalytic systems. Regarding the literature on basic properties of carbon materials, the reader is referred to the extensive collection of review papers published in the series Chemistry and Physics of Carbon. Editors P.L.

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Section: Carbon As Catalystmentioning

confidence: 99%

Carbons

Schlögl

2008

Handbook of Heterogeneous Catalysis

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“…[185] Although carbons are frequently used as catalyst supports, they may also be used as catalysts in their own right [186], [187]. Carbons exist in a variety of thermodynamic phases (allotropes of carbon) and metastable structures, which are often ill-defined (see also → Carbon).…”

Section: Carbides and Nitridesmentioning

confidence: 99%

Heterogeneous Catalysis and Solid Catalysts

Knözinger¹,

Kochloefl²

2003

Ullmann's Encyclopedia of Industrial Chemistry

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“…The recent papers report the superior performance of nitrogen-containing activated carbons in SO 2 retention [4], NO x adsorption and catalytic reduction [5][6][7], catalytic dechlorination [8] and sorption of transition metal cations [9]. The adsorption properties of the N-carbons are influenced by the chemical nature of nitrogen surface groups, the pyridinic and quaternary nitrogen being most effective in the specific adsorption.…”

Section: Introductionmentioning

confidence: 98%