Mechanism of Ozone Decomposition on a Manganese Oxide Catalyst. 2. Steady-State and Transient Kinetic Studies

and, Wei Li†; Oyama, S. Ted

doi:10.1021/ja9814422

Cited by 227 publications

(164 citation statements)

References 14 publications

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“…Table 4, the pre-exponential factor for step (1) held a very large number, 1.50×10 19 ±1.2×10 5 , whereas the values for the following two steps involved in the ozone decomposition are low, namely, 4.4±2.1 and 26.0±18.8, indicating that the first step was much faster than the subsequent two steps. These results are consistent with the conclusion by Oyama et al [27,28] that step (1) by itself is faster than steps (2) and (3).…”

Section: Model Discrimination and Parameter Estimationsupporting

confidence: 93%

“…The L-H d model also consists of two cycles, which follow the conclusion from the systematic study by Oyama et al [10,28], particularly with regard to the results of in situ Raman spectroscopy. The ozone decomposition cycle in the present study [i.e., steps (1)- (3)] is similar to a previously reported cycle [27,28], and the difference originates from toluene. In the present study, the s2 (graphene) site can be used for toluene adsorption because two active sites exist [step (4) First, the last step in the L-H d mechanism can be considered a slow step for catalytic ozonation of toluene, and the following steps were kinetically meaningless [10,24].…”

Section: L-h Kinetic Model Developmentsupporting

confidence: 90%

“…ozone decomposition over MnO 2 sites, which was the same as the classical explanation proposed by Oyama et al [27,28]; and toluene adsorption, which occurred on graphene sites.…”

Section: S2-s6 As Shown Insupporting

confidence: 80%

“…In our previous work [26], we found that pristine graphene showed some activity for ozone decomposition while MnO 2 exhibited much higher decomposition rate than that on graphene (around 10 times), which was attributed to its superior ability to adsorb ozone [27].…”

Section: L-h Kinetic Model Developmentmentioning

confidence: 89%

“…In this mechanism, the MnO 2 sites are reserved for ozone adsorption according to a classical ozone decomposition mechanism [27,28], whereas graphene offers sites for toluene adsorption. The L-H d mechanism has been commonly used to understand catalytic reactions [29][30][31][32]; however, to the best of our knowledge, no studies were reported on understanding catalytic ozonation of VOCs by the L-H d mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Yao

Hui

et al. 2017

Chemical Engineering Journal

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe catalytic ozonation of VOCs is a promising approach for degradation of indoor VOCs, such as gaseous toluene. However, the mechanism and relevant kinetic steps involved in this reaction remain unclear. In this study, the catalytic ozonation of toluene over MnO 2 /graphene was investigated using the empirical power law model and classic Langmuir-Hinshelwood single-site (denoted as L-H s ) mechanism. The apparent activation energy determined using the power law model was 29.3±2.5 kJ mol −1 . This finding indicated that the catalytic ozonation of toluene over MnO 2 /graphene was a heterogeneous reaction, and the Langmuir-Hinshelwood mechanism was applicable. However, the L-H s mechanism did not fit the experimental data, suggesting that the reaction was non-single-site governed. A novel Langmuir-Hinshelwood dual-site (denoted as L-H d ) mechanism was then proposed to explain the experimental observations of the catalytic ozonation of toluene over MnO 2 /graphene through a steady-state kinetic study. This mechanism was based on the hypothesis that MnO 2 was responsible for ozone decomposition and toluene adsorption on graphene; these two types of adsorption were coupled by an adjacent attack. Furthermore, XPS results confirmed the presence of a strong connection between MnO 2 and graphene sites on the surface of MnO 2 /graphene. This connection allowed the adjacent attack and validated the dual-site mechanism. The L-H d model was consistent with the predicted reaction rate of toluene removal with a correlation coefficient near unity (r 2 = 0.9165). Moreover, the physical criterion was in accordance with both enthalpy and entropy of toluene adsorption constraints. Fulfillment of mathematical and physical criteria indicated the catalytic ozonation of toluene over MnO 2 /graphene can be well described by the L-H d mechanism. This study helps understand the catalytic ozonation of toluene over MnO 2 /graphene in a closely mechanistic view.

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Section: Model Discrimination and Parameter Estimationsupporting

confidence: 93%

Section: L-h Kinetic Model Developmentsupporting

confidence: 90%

“…ozone decomposition over MnO 2 sites, which was the same as the classical explanation proposed by Oyama et al [27,28]; and toluene adsorption, which occurred on graphene sites.…”

Section: S2-s6 As Shown Insupporting

confidence: 80%

Section: L-h Kinetic Model Developmentmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Yao

Hui

et al. 2017

Chemical Engineering Journal

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Reactive Uptake of Sulfur Dioxide and Ozone on Volcanic Glass and Ash at Ambient Temperature

et al. 2017

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The atmospheric impacts of volcanic ash from explosive eruptions are rarely considered alongside those of volcanogenic gases/aerosols. While airborne particles provide solid surfaces for chemical reactions with trace gases in the atmosphere, the reactivity of airborne ash has seldom been investigated. Here we determine the total uptake capacity (NiM) and initial uptake coefficient (γM) for sulfur dioxide (SO2) and ozone (O3) on a compositional array of volcanic ash and glass powders at ~25°C in a Knudsen flow reactor. The measured ranges of NiSO2 and γSO2 (1011–1013 molecules cm−2 and 10−3–10−2) and NiO3 and γO3 (1012–1013 molecules cm−2 and 10−3–10−2) are comparable to values reported for mineral dust. Differences in ash and glass reactivity toward SO2 and O3 may relate to varying abundances of, respectively, basic and reducing sites on these materials. The typically lower SO2 and O3 uptake on ash compared to glass likely results from prior exposure of ash surfaces to acidic and oxidizing conditions within the volcanic eruption plume/cloud. While sequential uptake experiments overall suggest that these gases do not compete for reactive surface sites, SO2 uptake forming adsorbed S(IV) species may enhance the capacity for subsequent O3 uptake via redox reaction forming adsorbed S(VI) species. Our findings imply that ash emissions may represent a hitherto neglected sink for atmospheric SO2 and O3.

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Reactions of Peroxides on Solid Surfaces

Mello

González‐Núñez

2014

Patai's Chemistry of Functional Groups

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This article describes the different roles that solid surfaces play in heterogeneous reactions involving peroxides, namely, (i) the solid surface interacts with the peroxide in the absence of any other substrate, (ii) the solid surface promotes the reaction activating either the peroxide or the substrate, (iii) the peroxide forms part of the solid active surface, and (iv) the substrate forms part of the active surface. The chapter covers reactions involving peroxides or discrete peroxydic transient species on solid surfaces or at solid–liquid and solid–gas interfaces, and provides general descriptions of different solid materials, details on reaction conditions, and synthetic procedures for solid‐supported reagents.

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Mechanism of Ozone Decomposition on a Manganese Oxide Catalyst. 2. Steady-State and Transient Kinetic Studies

Cited by 227 publications

References 14 publications

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Reactive Uptake of Sulfur Dioxide and Ozone on Volcanic Glass and Ash at Ambient Temperature

Reactions of Peroxides on Solid Surfaces

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