Elementary reaction pathway study and a deduced macrokinetic model for the unified understanding of Ni-catalyzed steam methane reforming

Ke, Changming; Lin, Zijing

doi:10.1039/c9re00460b

Cited by 8 publications

(10 citation statements)

References 61 publications

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“…However, when the immobile model is considered, CO 2 is produced from CO oxidation on the surface. The different desorption models used could not show influence on the mechanism of CO formation on Ni(111), and the path of CH* + O* → CHO* + ∗ → CO* + H* is favored, in good agreement with the results reported in the literature. − …”

Section: Resultssupporting

confidence: 88%

First-Principles-Based Microkinetic Modeling of Methane Steam Reforming with Improved Description of Product Desorption

Zhu

Yang

2021

J. Phys. Chem. C

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The method combining density functional theory (DFT) calculations with microkinetic modeling has attracted increasing attention in obtaining a deeper understanding of catalytic reactions. While product desorption is conventionally regarded as an equilibrated process in the microkinetic modeling, it might be influential to product selectivity when competing reactions should be considered. In this work, a complex reaction network is established first for the methane steam reforming reaction using the equilibrium and immobile models over Ni, Pd, and Pt surfaces. This provides a basis to further investigate the reaction mechanism and kinetic modeling results. The results show that when different desorption models are considered, the total activity regarding methane conversion and the coverage and DRC value of the main species at the steady state are the same on each surface. In contrast, the mechanism of CO2 formation is varied based on different desorption models. Consequently, the rate and selectivity of CO2 generation on each metal catalyst are significantly improved when the barrier of CO desorption is considered in the microkinetic modeling compared with the modeling only with barrierless CO desorption.

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Section: Resultssupporting

confidence: 88%

First-Principles-Based Microkinetic Modeling of Methane Steam Reforming with Improved Description of Product Desorption

Zhu

Yang

2021

J. Phys. Chem. C

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“…The catalyzing effect of H-bond on oxhydryl dehydrogenation can also be seen in the dehydrogenation of OH* adsorbed on Ni(111) [42]. Figure 3 compares the activation energies, initial and transition state structures and charge distributions of OH* dehydrogenations with and without co-adsorbed neighboring OH*.…”

Section: Dehydrogenation Of Oh* Assisted By H-bond Of O-h•••oh and O-mentioning

confidence: 91%

Catalytic Effect of Hydrogen Bond on Oxhydryl Dehydrogenation in Methanol Steam Reforming on Ni(111)

Lin

2020

Molecules

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Dehydrogenation of H3COH and H2O are key steps of methanol steam reforming on transition metal surfaces. Oxhydryl dehydrogenation reactions of HxCOH (x = 0–3) and OH on Ni (111) were investigated by DFT calculations with the OptB88-vdW functional. The transition states were searched by the climbing image nudged elastic band method and the dimer method. The activation energies for the dehydrogenation of individual HxCOH* are 68 to 91 kJ/mol, and reduced to 12–17 kJ/mol by neighboring OH*. Bader charge analysis showed the catalysis role of OH* can be attributed to the effect of hydrogen bond (H-bond) in maintaining the charge of oxhydryl H in the reaction path. The mechanism of H-bond catalysis was further demonstrated by the study of OH* and N* assisted dehydrogenation of OH*. Due to the universality of H-bond, the H-bond catalysis shown here, is of broad implication for studies of reaction kinetics.

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“…117,118 Methane possessing the highest H/C ratio among the hydrocarbons is considered as a suitable source of hydrogen, but SRM routes generally require high reaction temperatures. [119][120][121] Recently, photothermal SRM process has attracted wide attention from the researchers, which enables to realize SRM with better catalytic performance under the conditions of relatively low temperatures than conventional thermocatalysis. 117,118,[122][123][124][125][126][127][128] TiO 2 has been widely used as an ideal catalyst and support due to its high photocatalytic activity and low cost.…”

Section: Photothermal Srmmentioning

confidence: 99%

Research progress on methane conversion coupling photocatalysis and thermocatalysis

et al. 2021

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Conversion of methane into value-added chemicals is of significance for methane utilization and industrial demand of primary chemical products. The barrier associated with the nonpolar structure of methane and the high bond energy C-H bond (4.57 eV) makes it difficult to realize methane conversion and activation under mild conditions. The photothermal synergetic strategy by combining photon energy and thermo energy provides an advanced philosophy to achieve efficient methane conversion. In this review, we overview the current pioneering studies of photothermal methane indirect conversion and present the methane direct conversion by the way of photocatalysis and thermocatalysis to provide a fundamental understanding of methane activation. Finally, we end this review with a discussion on the remaining challenges and perspectives of methane direct conversion over single-atom catalysts via photothermal synergetic strategy.

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Elementary reaction pathway study and a deduced macrokinetic model for the unified understanding of Ni-catalyzed steam methane reforming

Abstract: DFT based microkinetics and macrokinetics that give quantitative explanations of the Ni-catalyzed steam methane reforming reactions.

Cited by 8 publications

References 61 publications

First-Principles-Based Microkinetic Modeling of Methane Steam Reforming with Improved Description of Product Desorption

First-Principles-Based Microkinetic Modeling of Methane Steam Reforming with Improved Description of Product Desorption

Catalytic Effect of Hydrogen Bond on Oxhydryl Dehydrogenation in Methanol Steam Reforming on Ni(111)

Research progress on methane conversion coupling photocatalysis and thermocatalysis

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