Reaction of Nitrogen Oxides with Black Carbon: An FT-IR Study

Smith, D. Moody; Welch, W. F.; Graham, Susan M.; Chughtai, A. R.; Wicke, Brian G.; Grady, Karen A.

doi:10.1366/0003702884429247

Cited by 35 publications

(14 citation statements)

References 14 publications

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“…A second series of experiments was performed where NO reacted with grey soot, after reaction with a known quantity of HNO 3 . NO is unreactive towards fresh unexposed soot samples, 29,30 a result checked often in reference for the present soot samples, indicating that the observed reaction corresponds to NO reacting either with HNO 3 adsorbed on the soot or with a reaction product following the reaction of HNO 3 on soot. A small rate of HONO desorption is observed as may be seen in Fig.…”

Section: Resultssupporting

confidence: 70%

Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

Salgado

Rossi

2002

Phys. Chem. Chem. Phys.

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The reaction of HNO 3 with decane (C 10 H 22 ) soot generated in the laboratory has been studied in a Knudsen flow reactor. Two different types of soot were produced: Soot originating from a rich flame of decane and air ('' grey '' soot) and soot generated from a leaner flame of decane and air ('' black '' soot). Both HNO 3 uptake and product release have been observed. Whereas soot from a rich decane flame leads to HONO as the main product, NO and small amounts of NO 2 are observed from soot generated in a lean flame. A reaction mechanism is proposed in which HNO 3 is reduced to HONO, which is released into the gas phase on grey soot, but undergoes decomposition reactions on black soot to NO and NO 2, the latter of which also reacts on black soot to produce additional NO. Experiments on black soot show that at [HNO 3 ] > 10 11 molecule cm À3 a higher order process is induced which is associated with an additional production of NO and NO 2 . Further studies of the reaction of gaseous NO with adsorbed HNO 3 reveal a slow reaction leading to HONO and NO 2 . Both initial uptake (g 0 ) of HNO3 as well as steady state uptake probabilities (g ss ) have been obtained: g 0 ¼ (4.6 AE 2.3) Â 10 À3 and g ss ¼ (5.2 AE 1.3) Â 10 À4 for reaction on grey soot and g 0 ¼ (2.0 AE 0.1) Â 10 À2 and g ss ¼ (4.6 AE 1.6) Â 10 À3 for black soot, using the geometric surface area over which the samples are spread.

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Section: Resultssupporting

confidence: 70%

Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

Salgado

Rossi

2002

Phys. Chem. Chem. Phys.

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“…Furthermore, several theoretical studies have been recently devoted to the interaction between nitrogen oxides and carbonaceous surfaces, most of them considering interactions with the unsaturated edges of carbon clusters 16−18 or with atom vacancies at the surface of graphite 19,20 because the bare surface of carbon materials is expected to be less reactive. 21 Here, we choose to characterize the interaction between NO and carbonaceous clusters modeling the surface of soot because this radical species has not been considered much in the literature, at least from a theoretical point of view. Moreover, the few studies especially devoted to the adsorption of NO on a perfect carbonaceous surface (i.e., a surface without any defect) have led to significantly different results especially in terms of adsorption energies, 22−24 the calculated values being in addition far from the heat of adsorption experimentally measured at low temperature on graphitized carbon (values between −4.3 and −2.9 kcal/mol).…”

Section: Introductionmentioning

confidence: 99%

First-Principles Study of the Interaction between NO and Large Carbonaceous Clusters Modeling the Soot Surface

et al. 2014

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First-principles calculations are performed to characterize the NO adsorption on large carbonaceous clusters modeling the surface of soot. Adsorption on the face and on the edges of perfect and defective clusters is considered in the calculations. It is shown that the first situation corresponds to physisorption and requires taking into account long-range dispersion interactions in the calculations. In contrast, interaction of NO with the unsaturated edge of a defective cluster leads preferentially to a C-N rather than to a C-O chemical binding. This indicates that soot may be an efficient sink for NO in the troposphere only if it contains a high number of unsaturated carbon atoms. From a more fundamental point of view, this study also clearly evidences that quantum calculations have to be carefully conducted when considering the interaction between radical species and carbonaceous surfaces. Problems encountered with the choice of the functional used in density functional theory approaches as well as with the size of the basis set, spin multiplicity, and spin contamination have to be systematically addressed before any relevant conclusion can be drawn.

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“…Smith and coworkers have studied the N02-amorphous carbon interaction at higher pressure with respect to the surface adsorbates which they studied using transmission FTIR. 13 One of the conclusions of their work was that only 1% or so of the NO2 disappearing from the gas phase is observable by FTIR absorption spectroscopy as C-NO2 or C-ONO functionalities.14 A fairly complex dual-site mechanism was proposed in which both N02 as well as N2O4 adsorbed on amorphous carbon at pressures from 5 to 120 Torr.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Chemical Kinetics of NO2 on Amorphous Carbon at Ambient Temperature

Tabor¹,

Gutzwiller²,

Rossi³

1994

J. Phys. Chem.

110

107

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A low-pressure reactor was used to study the heterogeneous chemistry of NO2 interacting with three types of amorphous carbon with widely differing physicochemical properties at ambient temperature. Theuptake kinetics and the resulting products were measured using molecular beam sampled electron-impact mass spectrometry and in situ laser-induced fluorescence. The only major product resulting from the heterogeneous interaction of NO2 with all three carbon samples was NO with the oxidation product of carbon apparently remaining on the surface at ambient temperature. Both pulsed valve dosing and steady-state experiments were performed and revealed a complex reaction mechanism for both the uptake as well as product formation. The initial uptake coefficient yo for NO2 was (6.4 f 2.0) X I t 2 and proved to be identical for all three types of amorphous carbon.The initial NO2 uptake rate was mass independent and scaled with the external surface. Applying a simple chemical kinetic model to both pulsed dosing and steady state experiments resulted in an effective surface for uptake on amorphous carbon ranging between factors of 2.8 and 8.4 larger than the geometrical surface area but inversely proportional to the measured BET surface area of the three types of amorphous carbon. The chemical kinetic model included competing processes between Langmuir-type adsorption and inhibition controlling the adsorption kinetics of NO2 and revealed that the NO generation rate differed greatly between the three carbon samples examined. All samples showed saturation effects of differing degree that were partially reversible through prolonged pumping at 1 V Torr and/or heating. Virgin amorphous carbon samples did not take up H20 vapor at 20 mTorr, and no HONO and/or HNO3 was detected in simultaneous NO2/H2O exposure experiments. CO and C02 weredetected when previously dosed amorphous carbon was heated by an incandescent lamp. Upon heating a sample previously exposed to NO2, a MS signal m / e 62 originating from NO3 and/or N205 was detected.

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Reaction of Nitrogen Oxides with Black Carbon: An FT-IR Study

Cited by 35 publications

References 14 publications

Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

First-Principles Study of the Interaction between NO and Large Carbonaceous Clusters Modeling the Soot Surface

Heterogeneous Chemical Kinetics of NO2 on Amorphous Carbon at Ambient Temperature

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Reaction of Nitrogen Oxides with Black Carbon: An FT-IR Study

Cited by 35 publications

References 14 publications

Heterogeneous reactions of HNO3with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

Heterogeneous reactions of HNO3with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

First-Principles Study of the Interaction between NO and Large Carbonaceous Clusters Modeling the Soot Surface

Heterogeneous Chemical Kinetics of NO2 on Amorphous Carbon at Ambient Temperature

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Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics

Heterogeneous reactions of HNO₃with flame soot generated under different combustion conditions. Reaction mechanism and kinetics