Kinetics of Catalytic Dehydrogenation of Propane over Pt-Based Catalysts

Sui, Zhi‐Jun; Zhu, Yi‐An; Li, Ping; Zhou, Xinggui; Chen, De

doi:10.1016/b978-0-12-419974-3.00002-6

Cited by 22 publications

(28 citation statements)

References 120 publications

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“…However, in contrast with the results from MTD calculations, subsequent C–H bond breaking (in the case R = H) is not favored. 38 − 40 This difference of reactivity is consistent with the significantly higher selectivity and resulting higher coking resistance of Pt 2 Ga compared to Pt.…”

Section: Results and Discussionsupporting

confidence: 64%

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

Payard

Rochlitz

Searles

et al. 2021

JACS Au

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Nonoxidative dehydrogenation of light alkanes has seen a renewed interest in recent years. While PtGa systems appear among the most efficient catalyst for this reaction and are now implemented in production plants, the origin of the high catalytic performance in terms of activity, selectivity, and stability in PtGa-based catalysts is largely unknown. Here we use molecular modeling at the DFT level on three different models: (i) periodic surfaces, (ii) clusters using static calculations, and (iii) realistic size silica-supported nanoparticles (1 nm) using molecular dynamics and metadynamics. The combination of the models with experimental data (XAS, TEM) allowed the refinement of the structure of silica-supported PtGa nanoparticles synthesized via surface organometallic chemistry and provided a structure–activity relationship at the molecular level. Using this approach, the key interaction between Pt and Ga was evidenced and analyzed: the presence of Ga increases (i) the interaction between the oxide surface and the nanoparticles, which reduces sintering, (ii) the Pt site isolation, and (iii) the mobility of surface atoms which promotes the high activity, selectivity, and stability of this catalyst. Considering the complete system for modeling that includes the silica support as well as the dynamics of the PtGa nanoparticle is essential to understand the catalytic performances.

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Section: Results and Discussionsupporting

confidence: 64%

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

Payard

Rochlitz

Searles

et al. 2021

JACS Au

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“…The activation energy of the catalysts in this work is in the range of 60-120 kJ/mol, which is reasonable compared to the results reported in the literature. 2,47,48 The activation energy for the catalyst without H2S addition is 62 kJ/mol, while the ones for the catalysts with 3 and 9 ppm of H2S addition increase to 71 kJ/mol and 78 kJ/mol, respectively. Since the activation energy would decrease with less coke deposited on Pt surfaces during PDH based on the literatures, 14,49,50 the increase of activation energy in this work could be ascribed to the presence of H2S, and this effect was investigated by DFT calculations in section 3.4.4.…”

Section: Effect Of H 2 S Addition On Activation Energymentioning

confidence: 99%

The role of H₂S addition on Pt/Al₂O₃ catalyzed propane dehydrogenation: a mechanistic study

Wang

Zhang

Jiang

et al. 2019

Catal. Sci. Technol.

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“…[11][12][13] However, coking and deactivation of this kind of catalyst are still inevitable problems. 14 In industrial practice, the co-feed of hydrogen 7,[15][16][17][18] or steam 19 with propane is used to enhance the performance of platinum-based catalysts. The presence of hydrogen can contribute to higher propene selectivity and lower coking rates.…”

Section: Introductionmentioning

confidence: 99%

“…Steam has been widely used as an energy carrier, a coke remover and a diluent in dehydrogenation processes. 19,22,23 Introducing steam into the feed can strengthen PDH processes by increasing the propane equilibrium conversion and lowering the temperature drop of the adiabatic dehydrogenation reactors. 19 Dong et al 24 found that under the same propane partial pressure, steam can contribute to higher propene yield compared with that in nitrogen atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Insights into the effects of steam on propane dehydrogenation over a Pt/Al₂O₃ catalyst

Shan

Zhu

Sui

et al. 2015

Catal. Sci. Technol.

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Catalytic propane dehydrogenation over an alumina supported Pt catalyst in the presence of steam is carried out and it is found that the catalyst activity is increased and the apparent activation energy lowered due to the presence of steam. Three possible mechanisms, i.e. co-adsorption, Langmuir-Hinshelwood and Eley-Rideal, of changes in energetics and pathways for propane dehydrogenation due to the presence of steam are explored by DFT calculation. The results show that co-adsorption of C 3 species with the surface oxygenated species would elevate dehydrogenation energy barriers due to repulsion interactions between them. Surface -OH is more active than surface -O in activating C-H bond in propane and propyl species through either Langmuir-Hinshelwood or Eley-Rideal mechanism and plays an important role in propane dehydrogenation with steam. The Langmuir-Hinshelwood mechanism is kinetically favorable, in which the activations of the first H in propane by surface -OH are the rate determining steps, but the activation energies are higher than that on clean Pt(111) surface. The observed enhanced catalyst's activity is ascribed to the lowered coking rates as well as the changes in surface coverage due to the co-adsorption of mechanism. For PDH under steam atmosphere, the role of surface -OH is essential, most likely through Langmuir-Hinshelwood mechanism, in which the first C-H bond activation is the rate determining step in the overall PDH reaction route. The promoting effect of steam can be ascribed to the removal of cokes deposited on active Pt surfaces and the changes of adsorption species coverage on Pt surface.

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Kinetics of Catalytic Dehydrogenation of Propane over Pt-Based Catalysts

Cited by 22 publications

References 120 publications

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

The role of H₂S addition on Pt/Al₂O₃ catalyzed propane dehydrogenation: a mechanistic study

Insights into the effects of steam on propane dehydrogenation over a Pt/Al₂O₃ catalyst

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Kinetics of Catalytic Dehydrogenation of Propane over Pt-Based Catalysts

Cited by 22 publications

References 120 publications

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

Dynamics and Site Isolation: Keys to High Propane Dehydrogenation Performance of Silica-Supported PtGa Nanoparticles

The role of H2S addition on Pt/Al2O3 catalyzed propane dehydrogenation: a mechanistic study

Insights into the effects of steam on propane dehydrogenation over a Pt/Al2O3 catalyst

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The role of H₂S addition on Pt/Al₂O₃ catalyzed propane dehydrogenation: a mechanistic study

Insights into the effects of steam on propane dehydrogenation over a Pt/Al₂O₃ catalyst