Vanadium Nitride Catalysts: Synthesis and Evaluation forn-Butane Dehydrogenation

Kwon, Hyuk-Sung; Choi, Sunghyun; Thompson, Levi T.

doi:10.1006/jcat.1999.2450

Cited by 69 publications

(51 citation statements)

References 16 publications

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“…At this point we must indicate that V4O9 can be easily formed by treating V2O5 with sulphur [26], and it is an intermediate product during the preparation of vanadium nitrides [27]. In fact, by the temperatureprogrammed reaction of V2O5 with NH3 the following sequence has been proposed:…”

Section: The Characterization Results Carried Out By Raman and Exafs-mentioning

confidence: 99%

Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H2S to sulphur

Holgado¹,

Soriano²,

Jiménez-Jiménez³

et al. 2010

Catalysis Today

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(2010). Operando XAS and Raman study of the structure of supported vanadium oxide during the oxidation of H2S to sulphur. Catalysis Today. 155(3-4):296-301. doi:10.1016/j.cattod.2010.02.050. 1Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H2S to sulphur AbstractThe modification of crystalline phases of a vanadium oxide supported on mesoporous zirconium phosphate during the partial oxidation of H2S to sulphur has been studied by using an operando Raman-GC approach and XAS in reaction conditions. The catalyst, mainly presenting crystalline V2O5, is transformed during the oxidation of H2S at 200ºC, presenting crystals of V4O9, which is identified by the presence of a band at ca.900 cm -1 in the Raman spectra (using a 785 nm line of an Argon ion laser) and by the presence of a pre-edge at 5469.8 eV (and a main-edge at 5482.2 eV) in XANES spectra.At the same time, it is observed a high conversion of H2S to sulphur (the main reaction product) and SO2 (as minority). Both activity and selectivity depend on the time on stream. In this way, the selectivity to SO2 decreases from ca. 5 to 1% with the time on Keyword: Operando, RAMAN, EXAFS, XANES, partial oxidation of hydrogen sulphide, vanadium oxides supported on mesoporous zirconium phosphate.3

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Section: The Characterization Results Carried Out By Raman and Exafs-mentioning

confidence: 99%

Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H2S to sulphur

Holgado¹,

Soriano²,

Jiménez-Jiménez³

et al. 2010

Catalysis Today

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“…We must indicate that this crystalline structure can be easily formed by a partial reduction of V2O5 [39,40]. In addition V4O9 can be also easily oxidized to V2O5 in the presence of O2 at 200-250ºC [40].…”

Section: General Remarksmentioning

confidence: 95%

Selective oxidation of H2S to sulfur over vanadia supported on mesoporous zirconium phosphate heterostructure

Soriano

Jiménez-Jiménez

Concepción

et al. 2009

Applied Catalysis B: Environmental

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“…Appropriate metal sources in the pores of the carbon nitride are thus converted into metal nitride nanoparticles with defined nanoparticle size. Such metal nitride nanoparticles are interesting because of their potential application as abrasive materials, [21] catalysts, [22][23][24] or optoelectronic compounds. [25] Metal nitrides in general can be produced by the conversion of metals or metal oxides into the corresponding nitride using nitrogen sources, such as ammonia [26] or hydrazine [27,28] at high temperatures.…”

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confidence: 99%

Growth Confined by the Nitrogen Source: Synthesis of Pure Metal Nitride Nanoparticles in Mesoporous Graphitic Carbon Nitride

2007

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The synthesis of materials in nanometer-sized confinements, or "nanoreactors", is a suitable method for the preparation of nanoparticles. As "soft" organic nanoreactors, the synthesis of nanoparticles in micelles formed from surfactants [1] and block copolymers, [2][3][4][5][6] emulsions, [7][8][9] and gels [10] has been previously described. Soft nanoreactors often allow simple purification procedures, that is, the resulting nanoparticles can be separated from the self-assembled confinement in a nondestructive fashion. On the other hand, the softness of the reactor walls sometimes leads to unpredicted forms and shapes of the resulting nanoparticles, and the method is not often applicable for desirable nanoparticle compositions, which is because of the complex reactant mixtures present during synthesis. This is especially true for metal nitrides.Other approaches have used the confinement provided by the pore system of porous solids, mainly silica or alumina. These "hard" nanoreactors or exotemplates [11] inevitably result in exactly shaped replications of nanoparticles, nanowires, or even fully replicated mesoporous frameworks, depending on the structure and pore size of the confinement. Using this approach nanoparticles of metals, [12] metal oxides, [13][14][15] sulfides, [16] and nitrides, [17] as well as carbon nanostructures [18] and nanoparticles fabricated from high-temperature engineering plastics [19] have been produced. Still, a severe disadvantage of the hard-template approach is that isolation of the wanted materials is accompanied by the destruction of the confinement, often by using harmful etching reagents such as hydrofluoric acid. Furthermore, the incorporation of precursors into the confinement has to be ensured; an adequate pore filling and, if necessary, adequate mixing and stoichiometry of the starting components inside the nanopores is hard to control and obeys the statistics of small numbers.Here we report the synthesis of metal nitride nanoparticles in a new type of nanoconfined environment, namely mesoporous graphitic carbon nitride (mpg-C 3 N 4 ).[20] This approach adds two significant improvements to reported nanostructure synthesis using exotemplates: First, the reaction-confining matrix is thermally decomposed during synthesis, making additional purification and isolation steps obsolete. Second, the medium serves as a reagent in the nanoparticle synthesis by donating an excess of nitrogen during decomposition. Appropriate metal sources in the pores of the carbon nitride are thus converted into metal nitride nanoparticles with defined nanoparticle size. Such metal nitride nanoparticles are interesting because of their potential application as abrasive materials, [21] catalysts, [22][23][24] or optoelectronic compounds. [25] Metal nitrides in general can be produced by the conversion of metals or metal oxides into the corresponding nitride using nitrogen sources, such as ammonia [26] or hydrazine [27,28] at high temperatures.Also, the use of carbon nitride as a nitrogen source was descri...

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Vanadium Nitride Catalysts: Synthesis and Evaluation forn-Butane Dehydrogenation

Cited by 69 publications

References 16 publications

Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H2S to sulphur

Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H2S to sulphur

Selective oxidation of H2S to sulfur over vanadia supported on mesoporous zirconium phosphate heterostructure

Growth Confined by the Nitrogen Source: Synthesis of Pure Metal Nitride Nanoparticles in Mesoporous Graphitic Carbon Nitride

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