A study of small angle X-ray scattering from impregnated activated carbons

McDonald, Matthew J.; Smith, J.W.H.; Dahn, J. R.

doi:10.1016/j.carbon.2013.11.021

Cited by 11 publications

(7 citation statements)

References 28 publications

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“…Small-angle scattering has often been used to analyze nanostructures with multiple scales, such as nanocomposites, organic gels, and porous materials, − among others. In most works, however, the contribution of each scattering level is described using Guinier or Porod empirical models, with the prefactors considered as fitting parameters with no clear structural significance.…”

Section: Discussionmentioning

confidence: 99%

Small-Angle Scattering Analysis of Empty or Loaded Hierarchical Porous Materials

2016

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Small-angle scattering of X-rays (SAXS) or neutrons (SANS) is one of the few experimental methods that can in principle be used for the in situ study at the mesoscopic scale of physicochemical phenomena occurring inside nanoporous solids. However, the potential of the method is often limited by the lack of suitable data analysis methods to convert scattering data into real-space structural information. This is notably the case for most porous materials of practical interest, which exhibit a hierarchical structure with micro, meso, and macropores, with often a secondary material confined in the pores, such as in supported catalysts, as well as fuel-cell and battery materials. In the present paper, we propose a general analysis of X-ray scattering by this type of material. Assuming that each structural level is statistically independent from the others and has a distinct characteristic length scale, compact mathematical expressions are derived for the scattering of the entire hierarchical structure. The results are particularized to the SAXS analysis of SBA-15-ordered mesoporous silica loaded with copper nitrate as well as of supported catalysts obtained after heat treatment of that material. The SAXS data analysis shows that the nitrate fills both the micro- and mesopores of the material, while the metallic copper obtained after heat treatment is found only in the mesopores. Moreover, the mesoscopic-scale spatial distribution of the metal depends on the heat treatment, in line with earlier electron tomography studies. The main ideas underlying the SAXS data analysis were presented in a recent communication (Gommes Angew. Chem., Int. Ed. 2015, 54, 11804−11808). Here, we generalize the approach and provide a comprehensive discussion of how any level in a hierarchical structure contributes to its overall scattering pattern. The results, as well as the general modeling methodology, will be of interest to anyone interested in the quantitative analysis of small-angle scattering data of empty or loaded porous solids and more generally of any type of hierarchical material

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Section: Discussionmentioning

confidence: 99%

Small-Angle Scattering Analysis of Empty or Loaded Hierarchical Porous Materials

2016

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“…From intensity singularities within these zones, it is possible to estimate global size of the material, its shape, its surface and finally molecular arrangement of the analyzed material. Different studies intended to develop models describing the different apparent levels of structure, from macropores to atoms [189]. Du et al used SAXS to precisely characterize microporous zeolites, revealing consistent structural and surface information on the molecular scale [190].…”

Section: Particular Focus: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

“…As several studies deal with the separately SAXS analysis of carbonaceous materials and zeolites, SAXS consequently appears as an innovative technique for precise characterization of deactivating coke deposited over zeolite catalysts and is likely to face increasing interest. structure, from macropores to atoms [189]. Du et al used SAXS to precisely characteriz microporous zeolites, revealing consistent structural and surface information on the mo lecular scale [190].…”

Section: Particular Focus: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

Deactivation and Regeneration of Zeolite Catalysts Used in Pyrolysis of Plastic Wastes—A Process and Analytical Review

2021

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In catalytic industrial processes, coke deposition remains a major drawback for solid catalysts use as it causes catalyst deactivation. Extensive study of this phenomenon over the last decades has provided a better understanding of coke behavior in a great number of processes. Among them, catalytic pyrolysis of plastics, which has been identified as a promising process for waste revalorization, is given particular attention in this paper. Combined economic and environmental concerns rose the necessity to restore catalytic activity by recovering deactivated catalysts. Consequently, various regeneration processes have been investigated over the years and development of an efficient and sustainable process remains an industrial challenge. Coke removal can be achieved via several chemical processes, such as oxidation, gasification, and hydrogenation. This review focuses on oxidative treatments for catalyst regeneration, covering the current progress of oxidation treatments and presenting advantages and drawbacks for each method. Molecular oxidation with oxygen and ozone, as well as advanced oxidation processes with the formation of OH radicals, are detailed to provide a deep understanding of the mechanisms and kinetics involved (direct and indirect oxidation, reaction rates and selectivity, diffusion, and mass transfer). Finally, this paper summarizes all relevant analytical techniques that can be used to characterize deactivated and regenerated solid catalysts: XRD, N2 adsorption-desorption, SEM, NH3-TPD, elemental analysis, IR. Analytical techniques are classified according to the type of information they provide, such as structural characteristics, elemental composition, or chemical properties. In function of the investigated property, this overall tool is useful and easy-to-use to determine the adequate analysis.

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“…1 The essential element lithium is widely distributed in the Earth's crust, but is not regarded as an abundant element. [2][3][4][5] Indeed, the cost of the material increased after the commercialization of Li batteries. In contrast, sodium resources are in principle unlimited as the element is abundant in sea water and salt deposits.…”

Section: Introductionmentioning

confidence: 99%

Negative electrodes for Na-ion batteries

Dahbi

Yabuuchi

Kubota

et al. 2014

Phys. Chem. Chem. Phys.

578

491

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Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

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A study of small angle X-ray scattering from impregnated activated carbons

Cited by 11 publications

References 28 publications

Small-Angle Scattering Analysis of Empty or Loaded Hierarchical Porous Materials

Small-Angle Scattering Analysis of Empty or Loaded Hierarchical Porous Materials

Deactivation and Regeneration of Zeolite Catalysts Used in Pyrolysis of Plastic Wastes—A Process and Analytical Review

Negative electrodes for Na-ion batteries

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