Comprehensive investigation of methane conversion over Ni(111) surface under a consistent DFT framework: Implications for anti-coking of SOFC anodes

Han, Zongying; Yang, Zhibin; Han, Min−Koo

doi:10.1016/j.apsusc.2019.02.084

Cited by 61 publications

(43 citation statements)

References 88 publications

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“…84 In general, the estimated pre-exponential factors (eq S50) were identical to those reported by Dumesic et al 85 and estimated with the methodology proposed by Campbell et al 86 , Table 3. Similarly, the activation energies, as well as the standard reaction and adsorption enthalpies in this model, matched those reported in microkinetic modelling studies, 41,74,80 molecular simulations over Ni surfaces, 36,73,76,77,87,88 and experimental data. 11,71 For example, the activation energy for the oxygen-assisted C-H bond cleavage (step 1, Table 2) was in close agreement with the experimental value of 95kJ.mol -1 for Ni-Co catalyst 11 and microkinetic studies of 88−93kJ.mol -1 for Ni-based catalysts.…”

Section: Analysis Of the Solution Of The Kinetic Modelssupporting

confidence: 79%

“…87 The values of the activation energy and reaction enthalpy for the sequential H-abstraction reactions (step 2-4) were in the range of 65-130kJ.mol -1 , 36,41,73,74,80 and even their trend, i.e., a decrease in the activation energy upon the first H-abstraction and increase again for the last H-scission was similar to those predicted with molecular simulations. 36,73,76,88 Moreover, the steps involved in H2O production (steps 7 and 8) displayed activation energies of 89 ± 3 and 48 ± 3kJ.mol -1 , respectively, which were close to the values of 104 and 41kJ.mol -1 reported in microkinetic models. 74,80 Also, the corresponding standard enthalpies of 28 ± 1…”

Section: Analysis Of the Solution Of The Kinetic Modelssupporting

confidence: 77%

“…36,41,73,74,80 Finally, the current model presented energy barriers for the CO2 dissociation (step 5) and carbon oxidation (step 6) of 66 ± 2 and -95 ± 5kJ.mol -1 , respectively, that agreed with the ranges reported in the literature and that goes from 65-89kJ.mol -1 and 54-153kJ.mol -1 , respectively. 36,73,74,76,80,88 Figure 8. The coverages predicted for CO2, H2O, and CHx were lower than 0.001 so they were excluded from the analysis.…”

Section: Analysis Of the Solution Of The Kinetic Modelsmentioning

confidence: 99%

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Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

Sandoval-Bohorquez

Morales-Valencia²,

Castillo‐Araiza³

et al. 2021

Preprint

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The dry reforming of methane is a promising technology for the abatement of CH4 and CO2. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH4 rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a <a>metal−oxygen </a>pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO2; (3) the dissociation of CO2 can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH4 activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

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Section: Analysis Of the Solution Of The Kinetic Modelssupporting

confidence: 79%

Section: Analysis Of the Solution Of The Kinetic Modelssupporting

confidence: 77%

Section: Analysis Of the Solution Of The Kinetic Modelsmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

Sandoval-Bohorquez

Morales-Valencia²,

Castillo‐Araiza³

et al. 2021

Preprint

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“…Here, using a combination of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) and molecular modeling based on density functional theory (DFT), we present a comprehensive study of the MSR reaction on the surface of model Ni/CeO2(111) catalysts and compare with results reported for the extended Ni(111) surface in the literature. [21][22][23][24][47][48][49][50][51][52][53][54] We show that low-loaded Ni/CeO2 catalysts have sites with unique properties that result from the nature of both the metallic phase and the support as well as their interactions, which enable the facile activation of C−H and O−H bonds from CH4 and H2O, respectively. The calculated elementary dehydrogenation and oxidation steps along the MSR reaction reveal that the crucial step is the formation of a COH intermediate via the reaction of carbon atoms with OH groups, suppressing carbon deposition.…”

Section: Introductionmentioning

confidence: 84%

“…19 However, experimental and computational studies have shown that the reactions of carbonaceous species with oxygen to form the C-O bond also involve high energy barriers, and could therefore be rate-controlling. [20][21][22][23][24][25][26] Furthermore, in previous combined computational and in-situ spectroscopic studies, it was shown that well-dispersed small Ni nanoparticles supported on a non-reduced CeO2 surface can in fact activate CH4 at room temperature, with calculated energy barriers up to 80% lower than those for extended nickel surfaces. [27][28][29][30][31] This highlights the need to consider both the effect of the nature of the support and the metal loading to fully understand the mechanism governing the MSR reaction over supported metal catalysts, which is necessary for the development of improved catalytic systems.…”

Section: Introductionmentioning

confidence: 99%

Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and Role of Metal-Support Interactions

Salcedo¹,

Lustemberg²,

Rui³

et al. 2021

Preprint

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Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands the development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH4/H2O gas mixtures react with Ni/CeO2(111) surfaces to form OH, CHx and CHxO at 300 K. All these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process accelerates. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3–0.7 eV for the complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation are rate-determining steps, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interaction between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results could pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.

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Sustainable Ammonia Synthesis from Nitrogen and Water by One‐Step Plasma Catalysis

Zhang

Zhou

Shuai

et al. 2022

Energy & Environ Materials

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Sustainable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks is globally sought to replace the Haber–Bosch process. Here, using nitrogen and water as raw materials, a nonthermal plasma catalysis approach is demonstrated as an effective power‐to‐chemicals conversion strategy for ammonia production. By sustaining a highly reactive environment, successful plasma‐catalytic production of NH3 was achieved from the dissociation of N2 and H2O under mild conditions. Plasma‐induced vibrational excitation is found to decrease the N2 and H2O dissociation barriers, with the presence of matched catalysts in the nonthermal plasma discharge reactor contributing significantly to molecular dissociation on the catalyst surface. Density functional theory calculations for the activation energy barrier for the dissociation suggest that ruthenium catalysts supported on magnesium oxide exhibit superior performance over other catalysts in NH3 production by lowering the activation energy for the dissociative adsorption of N2 down to 1.07 eV. The highest production rate, 2.67 mmol gcat.−1 h−1, was obtained using ruthenium catalyst supported on magnesium oxide. This work highlights the potential of nonthermal plasma catalysis for the activation of renewable sources to serve as a new platform for sustainable ammonia production.

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Comprehensive investigation of methane conversion over Ni(111) surface under a consistent DFT framework: Implications for anti-coking of SOFC anodes

Cited by 61 publications

References 88 publications

Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and Role of Metal-Support Interactions

Sustainable Ammonia Synthesis from Nitrogen and Water by One‐Step Plasma Catalysis

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