References of "de Jong, Krijn"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailModeling reaction-limited Ostwald ripening of supported Ni catalysts in presence of CO: the role of particle size distribution
Gommes, Cédric ULg; Munnik, Peter; de Jongh, Petra et al

Poster (2014, March)

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailNanoparticle Growth in Supported Nickel Catalysts during Methanation Reaction-Larger is Better
Munnik, Peter; Velthoen, Marjolein; de Jongh, Petra et al

in Angewandte Chemie International Edition (2014)

A major cause of supported metal catalyst deactivation is particle growth by Ostwald ripening. Nickel catalysts, used in the methanation reaction, may suffer greatly from this through the formation of [Ni ... [more ▼]

A major cause of supported metal catalyst deactivation is particle growth by Ostwald ripening. Nickel catalysts, used in the methanation reaction, may suffer greatly from this through the formation of [Ni(CO)4]. By analyzing catalysts with various particle sizes and spatial distributions, the interparticle distance was found to have little effect on the stability, because formation and decomposition of nickel carbonyl rather than diffusion was rate limiting. Small particles (3–4 nm) were found to grow very large (20–200 nm), involving local destruction of the support, which was detrimental to the catalyst stability. However, medium sized particles (8 nm) remained confined by the pores of the support displaying enhanced stability, and an activity 3 times higher than initially small particles after 150 h. Physical modeling suggests that the higher [Ni(CO)4] supersaturation in catalysts with smaller particles enabled them to overcome the mechanical resistance of the support. Understanding the interplay of particle size and support properties related to the stability of nanoparticles offers the prospect of novel strategies to develop more stable nanostructured materials, also for applications beyond catalysis. [less ▲]

Detailed reference viewed: 31 (2 ULg)
Full Text
Peer Reviewed
See detailMesoporosity of Zeolite Y – 3D Quantitative Study by Image Analysis of Electron Tomograms
Zecevic, Jovana; Gommes, Cédric ULg; friedrich, Heiner et al

in Angewandte Chemie (International ed. in English) (2012), 51

Detailed reference viewed: 15 (1 ULg)
See detailCharacterization of nanometer-scale roughness in SBA-15 mesoporous silica using image analysis of electron tomograms
Friedrich, Heiner; Gommes, Cédric ULg; de Jongh, Petra et al

Conference (2009, September)

Detailed reference viewed: 1 (0 ULg)
See detailQuantization of pore corrugation in SBA-15 by image analysis of electron tomograms
Friedrich, Heiner; Gommes, Cédric ULg; de Jongh, Petra et al

Conference (2009, March)

Detailed reference viewed: 2 (0 ULg)
Full Text
Peer Reviewed
See detailQuantitative Structural Analysis of Binary Nanocrystal Superlattices by Electron Tomography
Friedrich, Heiner; Gommes, Cédric ULg; Overgaag, Karin et al

in Nano Letters (2009), 9

Binary nanocrystal superlattices, that is, ordered structures of two sorts of nanocolloids, hold promise for a series of functional materials with novel collective properties. Here we show that based on ... [more ▼]

Binary nanocrystal superlattices, that is, ordered structures of two sorts of nanocolloids, hold promise for a series of functional materials with novel collective properties. Here we show that based on electron tomography a comprehensive, quantitative, three-dimensional characterization of these systems down to the single nanocrystal level can be achieved, which is key in understanding the emerging materials properties. On four binary lattices composed of PbSe, CdSe, and Au nanocrystals, we illustrate that ambiguous interpretations based on two-dimensional transmission electron microscopy can be prevented, nanocrystal sizes and superlattice parameters accurately determined, individual crystallographic point and plane defects studied, and the order/disorder at the top and bottom surfaces imaged. Furthermore, our results suggest that superlattice nucleation and growth occurred at the suspension/air interface and that the unit cells of some lattices are anisotropically deformed upon drying. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Full Text
Peer Reviewed
See detailQuantitative Characterization of Pore Corrugation in Ordered Mesoporous Materials Using Image Analysis of Electron Tomograms
Gommes, Cédric ULg; Friedrich, Heiner; Wolters, Mariska et al

in Chemistry of Materials (2009), 21

Electron tomography and image analysis are combined to characterize ordered mesoporous silica SBA-15. The morphology of the mesopores with average diameter 6 nm is analyzed in terms of cylinders having ... [more ▼]

Electron tomography and image analysis are combined to characterize ordered mesoporous silica SBA-15. The morphology of the mesopores with average diameter 6 nm is analyzed in terms of cylinders having variable radii and centers that are statistically centered on the points of a distorted hexagonal lattice. The variations in the mesopore centers and radii add up and result in pore wall corrugation with amplitude of 1.6 nm. The correlation length of the corrugation along the pore axis was found to be 4-5 nm. The amplitude of the corrugation compared well with the 1.9 nm thick microporous corona obtained from X-ray diffraction (XRD). In general, the present approach provides a detailed microscopic 3D model of nanostructured materials that complements macroscopic measurements such as physisorption and XRD. [less ▲]

Detailed reference viewed: 39 (3 ULg)
Peer Reviewed
See detailNi/SiO2 Catalyst Preparation Studies using SBA-15 as a Model Support and quantitative Electron Tomography Characterisation
de Jongh, Petra; Friedrich, Heiner; Gommes, Cédric ULg et al

Poster (2008, September)

Detailed reference viewed: 1 (0 ULg)
See detailAnalysis of 3DTEM and SAXS of ordered mesoporous silica with the same stochastic morphological model
Gommes, Cédric ULg; Friedrich, Heiner; Wolters, Mariska et al

Scientific conference (2008, May)

Detailed reference viewed: 8 (0 ULg)
See detail3D covariance of ordered mesoporous materials and its modelling with random cylinders
Gommes, Cédric ULg; Friedrich, H; Wolters, M et al

Scientific conference (2008, February)

Detailed reference viewed: 5 (0 ULg)
Peer Reviewed
See detailQuantitative Morphological Studies of mesoporous Catalysts at Nanometer Scale Resolution
Ziese, Ulrike; Gommes, Cédric ULg; BLACHER, Silvia ULg et al

Poster (2005, August)

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailQuantitative morphological studies of mesoporous catalysts at nanometer scale resolution
Ziese, Ulrike; Gommes, Cédric ULg; Blacher, Silvia ULg et al

in Studies in Surface Science and Catalysis (2005), 158

We have combined electron tomography with posterior image processing for a quantitative morphological study of mesoporous catalysts at nanometer scale resolution. As a first example for the possibilities ... [more ▼]

We have combined electron tomography with posterior image processing for a quantitative morphological study of mesoporous catalysts at nanometer scale resolution. As a first example for the possibilities of the approach, pore size distributions of single particles of commercial USY and XVUSY zeolites were derived. [less ▲]

Detailed reference viewed: 58 (1 ULg)
Full Text
Peer Reviewed
See detailAssessment of the 3D Localization of Metallic Nanoparticles in Pd/SiO2 Cogelled Catalysts by Electron Tomography
Gommes, Cédric ULg; de Jong, Krijn; Pirard, Jean-Paul ULg et al

in Langmuir (2005), 21

The purpose of this study is to analyze the localization of palladium nanoparticles within their silica support, in two heterogeneous catalysts synthesized by the sol-gel process, with different metal ... [more ▼]

The purpose of this study is to analyze the localization of palladium nanoparticles within their silica support, in two heterogeneous catalysts synthesized by the sol-gel process, with different metal loadings. Electron tomography demonstrates that the palladium particles are localized deep inside the silica skeleton. The use of digital image analysis further shows that the dispersion of palladium is optimal in the sample with the lowest loading. The particles are regularly spaced in the middle of the silica skeleton, with a distance between them comparable to the diameter of the struts of silica. [less ▲]

Detailed reference viewed: 17 (1 ULg)