Understanding the gas transport in porous catalyst layers by using digital reconstruction techniques

Novák, Vladimír; Dudák, Michal; Kočí, Petr; Marek, M.

doi:10.1016/j.coche.2015.07.002

Cited by 14 publications

(7 citation statements)

References 50 publications

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“…For the investigation of pore structures relevant in catalysis with imaging techniques, a combination of different tomography methods, i.e., µ-CT, PXCT, and ET, is necessary. Porosity information from tomography techniques is valuable to describe the gas transport in pores [31].…”

Section: Introductionmentioning

confidence: 99%

Porosity and Structure of Hierarchically Porous Ni/Al2O3 Catalysts for CO2 Methanation

et al. 2020

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CO2 methanation is often performed on Ni/Al2O3 catalysts, which can suffer from mass transport limitations and, therefore, decreased efficiency. Here we show the application of a hierarchically porous Ni/Al2O3 catalyst for methanation of CO2. The material has a well-defined and connected meso- and macropore structure with a total porosity of 78%. The pore structure was thoroughly studied with conventional methods, i.e., N2 sorption, Hg porosimetry, and He pycnometry, and advanced imaging techniques, i.e., electron tomography and ptychographic X-ray computed tomography. Tomography can quantify the pore system in a manner that is not possible using conventional porosimetry. Macrokinetic simulations were performed based on the measures obtained by porosity analysis. These show the potential benefit of enhanced mass-transfer properties of the hierarchical pore system compared to a pure mesoporous catalyst at industrially relevant conditions. Besides the investigation of the pore system, the catalyst was studied by Rietveld refinement, diffuse reflectance ultraviolet-visible (DRUV/vis) spectroscopy, and H2-temperature programmed reduction (TPR), showing a high reduction temperature required for activation due to structural incorporation of Ni into the transition alumina. The reduced hierarchically porous Ni/Al2O3 catalyst is highly active in CO2 methanation, showing comparable conversion and selectivity for CH4 to an industrial reference catalyst.

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Section: Introductionmentioning

confidence: 99%

Porosity and Structure of Hierarchically Porous Ni/Al2O3 Catalysts for CO2 Methanation

et al. 2020

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“…Additionally, even though some experimental studies exist on the metal−support interactions, very few studies have quantitatively analyzed the role of metal−support interfacial contact on the performance of a three-way catalyst. Novak et al 16 reviewed multiscale modeling approaches and 3D digital washcoat reconstruction techniques and showed that a combination of these could be used to predict the effect of catalyst morphology on the light-off behavior. However, even the detailed models which consider the catalyst morphology do not consider the metal−support interactions at the crystallite scale, which are found to have a significant impact on the catalyst performance.…”

Section: Introductionmentioning

confidence: 99%

Crystallite-Scale Approach To Predict the Oxygen Storage Capacity of a Three-Way Catalyst for Natural Gas Applications

Rajbala

Bhatia

2019

Ind. Eng. Chem. Res.

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A model incorporating crystallite-scale features of a catalyst is developed to predict the oxygen storage capacity (OSC) of a Pd-containing three-way catalyst. The model predicts the effect of Pd crystallite size, Pd−ceria interfacial contact, and Pd dispersion on the spillover and reverse-spillover of oxygen between Pd and ceria, and the resulting OSC with H 2 and CH 4 as reductants. Consistent with the experimental findings, the model predicts that H 2 results in a higher OSC than CH 4 . The dependence of oxygen surface diffusivity on the temperature is used to predict the reported variation of OSC with temperature. The effective surface diffusivity with H 2 is estimated to be higher than that with CH 4 , which is attributed to the possible spillover of hydrogen in addition to the reverse spillover of oxygen. This work can be extended to gasoline applications and other transient catalytic systems where spillover and reverse spillover effects are significant.

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“…Morphological properties, including surface area, porosity, and tortuosity, are critical to catalysts in an electrochemical device. − These properties are related to the diffusion and dissolution of the reactants and products inside the catalysts’ structures. The morphological properties of operating devices can be linked to the electrochemical performance, and many studies have done so. ,− Though useful, more attention is needed to improve the catalyst design and synthesis.…”

Section: Applications Of X-ray Ct To In Situ and Operando Studies In ...mentioning

confidence: 99%

X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

Lang,

Kulkarni,

Foster

et al. 2023

Chem. Rev.

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Understanding the gas transport in porous catalyst layers by using digital reconstruction techniques

Cited by 14 publications

References 50 publications

Porosity and Structure of Hierarchically Porous Ni/Al2O3 Catalysts for CO2 Methanation

Porosity and Structure of Hierarchically Porous Ni/Al2O3 Catalysts for CO2 Methanation

Crystallite-Scale Approach To Predict the Oxygen Storage Capacity of a Three-Way Catalyst for Natural Gas Applications

X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

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