Studies of surface reactions of nitric oxide by nitrogen-15 isotope labeling. I. Reaction between nitric oxide and ammonia over supported platinum at 200-250.deg.

Otto, K.; Shelef, M.; Kummer, J. T.

doi:10.1021/j100707a017

Cited by 138 publications

(92 citation statements)

References 3 publications

(3 reference statements)

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“…However, gasphase H 2 was never observed in the 15 NO pulse in the present experiments in spite of the applied pressure conditions, which would favour its desorption. The discrepancy between the suggested reaction pathway of N 2 O formation via NH 2 -NO coupling [14] and the present experimental observations can be overcome by assuming participation of additional oxygencontaining species, which react with hydrogen atoms of the NH x (x = 1, 2) fragments. Such oxygen species can be oxygen atoms (Eqs.…”

Section: Primary Reaction Steps Of Nh 3 and No Interactioncontrasting

confidence: 89%

“…The formation of these products started above 473 K. The amount of formed H 2 O achieved a maximum at 573 K. A further temperature increase led to a decrease of the amount of H 2 O; it increased, however, again after passing through a minimum between 773 and 873 K. The formation of 14 N 2 and H 2 increased with temperature in accordance with an increased degree of NH 3 decomposition over oxygen-treated Pt gauze as reported by us previously [26]. The increase in the amount of 14 N 2 is the main product at higher temperatures. The decrease of the total nitrogen formation at elevated temperatures correlates with earlier observations [6,9,10].…”

Section: Reduction Of Nitric Oxide By Ammoniasupporting

confidence: 82%

“…These observations indicate that under conditions studied it is unlikely that nitrogen atoms participate in the formation of N 2 O. With respect to the alternative reaction pathways suggested in literature [3,9,10,14] NO via coupling between adsorbed NH x and NO species has to be considered. This reaction pathway suggested the formation of adsorbed hydrogen atoms, which can also recombine yielding H 2 .…”

Section: Primary Reaction Steps Of Nh 3 and No Interactionmentioning

confidence: 91%

“…N 2 O formation was only sporadically observed and discussed. The most informative insights into N 2 and N 2 O formation were derived using isotopically labelled molecules ( 15 NO [6] and 15 NH 3 [7,8,14]). The suggested concepts differ in the reaction pathways of product formation.…”

Section: Introductionmentioning

confidence: 99%

“…The suggested concepts differ in the reaction pathways of product formation. Earlier mechanisms [3,9,10,14] consider the dissociation of ammonia to NH 2 and hydrogen atoms, which in turn react with adsorbed NO yielding HNO species. HNO and NH 2 species participate in the reaction pathways leading to N 2 and N 2 O (Eqs.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic insights into the formation of N2O and N2 in NO reduction by NH3 over a polycrystalline platinum catalyst

Kondratenko

Baerns

2007

Applied Catalysis B: Environmental

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The reaction pathways of N 2 and N 2 O formation in the direct decomposition and reduction of NO by NH 3 were investigated over a polycrystalline Pt catalyst between 323 and 973 K by transient experiments using the temporal analysis of products (TAP-2) reactor. The interaction between nitric oxide and ammonia was studied in the sequential pulse mode applying 15 NO. Differently labelled nitrogen and nitrous oxide molecules were detected. In both, direct NO decomposition and NH 3 -NO interaction, N 2 O formation was most marked between 573 and 673 K, whereas N 2 formation dominated at higher temperatures. An unusual interruption of nitrogen formation in the 15 NO pulse at 473 K was caused by an inhibiting effect of adsorbed NO species. The detailed analysis of the product distribution at this temperature clearly indicates different reaction pathways leading to the product formation. Nitrogen formation occurs via recombination of nitrogen atoms formed by dissociation of nitric oxide or/and complete dehydrogenation of ammonia. N 2 O is formed via recombination of adsorbed NO molecules. Additionally, both products are formed via interactions between adsorbed ammonia fragments and nitric oxide. #

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Section: Primary Reaction Steps Of Nh 3 and No Interactioncontrasting

confidence: 89%

Section: Reduction Of Nitric Oxide By Ammoniasupporting

confidence: 82%

Section: Primary Reaction Steps Of Nh 3 and No Interactionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mechanistic insights into the formation of N2O and N2 in NO reduction by NH3 over a polycrystalline platinum catalyst

Kondratenko

Baerns

2007

Applied Catalysis B: Environmental

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GC/MSfor Combustion and Pyrolysis Research

Cizdziel

Chen

2010

Handbook of Combustion

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The ability to determine combustion and thermal decomposition (pyrolysis) products at trace concentrations can lead to important information on catalytic pathways, the degradation process itself, and structural (fingerprint) information on the parent molecule(s), among others. Gas chromatography coupled with mass spectrometry (GC/MS) is well suited to separate and identify the volatile molecules and molecular fragments generated by combustion and pyrolysis processes. Whereas, pyrolysis (conducted in an inert atmosphere) is often used as a sample introduction device directly coupled to GC/MS, combustion is generally carried out offline and its products are collected and analyzed with GC/MS, or even pyrolysis‐GC/MS. In the past few years, this powerful technique has been used to examine a variety of sample types for quite diverse applications. This chapter describes the state of the art and the progress of GC/MS for the measurement of combustion and pyrolysis products. An introduction to the technique, including the principles of GC/MS, is first provided, followed by a demonstration of the instrument's capabilities for combustion and pyrolysis research. All reports discussed herein were selected in part to demonstrate the diversity of current combustion and pyrolysis research using GC/MS. The present authors' studies with temperature‐programmed desorption in conjunction with GC/MS to characterize oxygen shuttling on the chars derived from different gaseous environment, are highlighted. Finally, the use of GC/MS in combination with isotope‐labeling techniques to reveal complex reaction pathways and mechanisms is discussed.

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Low‐Valent Manganese Atoms Stabilized on Ceria for Nitrous Oxide Synthesis

et al. 2023

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Nitrous oxide, N2O, exhibits unique reactivity in oxidation catalysis, but the high manufacturing costs limit its prospective uses. Direct oxidation of ammonia, NH3, to N2O can ameliorate this issue but its implementation is thwarted by suboptimal catalyst selectivity and stability, and the lack of established structure–performance relationships. Systematic and controlled material nanostructuring offers an innovative approach for advancement in catalyst design. Herein low‐valent manganese atoms stabilized on ceria, CeO2, are discovered as the first stable catalyst for NH3 oxidation to N2O, exhibiting two‐fold higher productivity than the state‐of‐the‐art. Detailed mechanistic, computational and kinetic studies reveal CeO2 as the mediator of oxygen supply, while undercoordinated manganese species activate O2 and facilitate N2O evolution via NN bond formation between nitroxyl, HNO, intermediates. Synthesis via simple impregnation of a small metal quantity (1 wt%) predominantly generates isolated manganese sites, while full atomic dispersion is achieved upon redispersion of sporadic oxide nanoparticles during reaction, as confirmed by advanced microscopic analysis and electron paramagnetic resonance spectroscopy. Subsequently, manganese speciation is maintained, and no deactivation is observed over 70 h on stream. CeO2‐supported isolated transition metals emerge as a novel class of materials for N2O production, encouraging future studies to evaluate their potential in selective catalytic oxidations at large.

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Studies of surface reactions of nitric oxide by nitrogen-15 isotope labeling. I. Reaction between nitric oxide and ammonia over supported platinum at 200-250.deg.

Cited by 138 publications

References 3 publications

Mechanistic insights into the formation of N2O and N2 in NO reduction by NH3 over a polycrystalline platinum catalyst

Mechanistic insights into the formation of N2O and N2 in NO reduction by NH3 over a polycrystalline platinum catalyst

GC/MSfor Combustion and Pyrolysis Research

Low‐Valent Manganese Atoms Stabilized on Ceria for Nitrous Oxide Synthesis

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