S. Dzwigaj | Sorbonne University (original) (raw)
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Papers by S. Dzwigaj
Microporous and Mesoporous Materials, 2012
Microporous and Mesoporous Materials, 2013
ABSTRACT NixSiBEA zeolites (x = 1–2 Ni wt.%) were prepared by a two-steps postsynthesis method wh... more ABSTRACT NixSiBEA zeolites (x = 1–2 Ni wt.%) were prepared by a two-steps postsynthesis method which consists of (1) creation of vacant T-sites by dealumination of tetraethylammonium BEA zeolite with nitric acid and then (2) impregnation of resulting SiBEA zeolite with an aqueous solution of Ni(NO3)2, following a drying (333 K) of as prepared NixSiBEA. The calcination of NixSiBEA at 773 K for 3 h in air leads to formation of C-NixSiBEA with an isolated pseudo-tetrahedral Ni(II) species incorporated in BEA framework as evidenced by combined use of XRD, DR UV–vis, XPS and TPR. The reduction of C-NixSiBEA (873 K, 3 h in flowing 10% H2/Ar) leads to formation of red-C-NixSiBEA with a very high dispersion of nickel (>65%) measured by oxygen chemisorption. The red-C-NixSiBEA catalysts were active in hydrodechlorination of chlorinated volatile organic compound (1,2-dichloroethane) at relatively low reaction temperatures (523–543 K) with a very high selectivity (90%) into desired product, ethylene. TPH experiments have shown that after hydrodechlorination of 1,2-dichloroethane a very little amount of carbonaceous and chlorine-containing species are present on spent NixSiBEA zeolite catalysts.
Microporous and Mesoporous Materials, 2013
ABSTRACT HAlBEA zeolite is prepared by calcination of parent TEABEA zeolite at 823 K for 3 h in a... more ABSTRACT HAlBEA zeolite is prepared by calcination of parent TEABEA zeolite at 823 K for 3 h in air following ionic exchange with NH4NO3 solution. NixHAlBEA zeolites are prepared by impregnation of HAlBEA with an aqueous solution of Ni(NO3)2, following a drying at 333 K to obtain NixHAlBEA. The calcination of HAlBEA and NixHAlBEA at 773 K for 3 h in air leads to the formation of C-HAlBEA and C–NixHAlBEA with appeared, for the latter, an octahedral and tetrahedral Ni(II) species incorporated in BEA framework as evidenced by XRD, DR UV–vis and XPS. Red-C-HAlBEA and red-C–NixHAlBEA are investigated as the catalysts in dehydrochlorination of 1,2-dichloroethane into vinyl chloride monomer in the presence of hydrogen at 503–523 K. Red-C-HAlBEA and red-C–Ni1.0HAlBEA show an excellent selectivity toward vinyl chloride (∼100%). Activity of HAlBEA and NixHAlBEA in the catalytic conversion of 1,2-dichloroethane strongly depends on the acidic properties of these materials and for the latter the catalytic activity depend on metal dispersion. The small Ni particles favor the dehydrochlorination of 1,2-dichloroethane to vinyl chloride. With increasing nickel particles size decreases activity of the red-C–NixHAlBEA catalysts. For these catalysts after kinetic run sintering of nickel phase is observed. Besides of carburization the nickel sintering is the main cause of red-C–NixHAlBEA deactivation. It is stronger for spent-red-C–Ni2.0HAlBEA with larger nickel particles than for red-C–Ni1.0HAlBEA containing smaller nickel particles (smaller than 5 nm).
The Journal of Physical Chemistry B, 2006
Microporous and Mesoporous Materials, 2012
Microporous and Mesoporous Materials, 2013
ABSTRACT NixSiBEA zeolites (x = 1–2 Ni wt.%) were prepared by a two-steps postsynthesis method wh... more ABSTRACT NixSiBEA zeolites (x = 1–2 Ni wt.%) were prepared by a two-steps postsynthesis method which consists of (1) creation of vacant T-sites by dealumination of tetraethylammonium BEA zeolite with nitric acid and then (2) impregnation of resulting SiBEA zeolite with an aqueous solution of Ni(NO3)2, following a drying (333 K) of as prepared NixSiBEA. The calcination of NixSiBEA at 773 K for 3 h in air leads to formation of C-NixSiBEA with an isolated pseudo-tetrahedral Ni(II) species incorporated in BEA framework as evidenced by combined use of XRD, DR UV–vis, XPS and TPR. The reduction of C-NixSiBEA (873 K, 3 h in flowing 10% H2/Ar) leads to formation of red-C-NixSiBEA with a very high dispersion of nickel (>65%) measured by oxygen chemisorption. The red-C-NixSiBEA catalysts were active in hydrodechlorination of chlorinated volatile organic compound (1,2-dichloroethane) at relatively low reaction temperatures (523–543 K) with a very high selectivity (90%) into desired product, ethylene. TPH experiments have shown that after hydrodechlorination of 1,2-dichloroethane a very little amount of carbonaceous and chlorine-containing species are present on spent NixSiBEA zeolite catalysts.
Microporous and Mesoporous Materials, 2013
ABSTRACT HAlBEA zeolite is prepared by calcination of parent TEABEA zeolite at 823 K for 3 h in a... more ABSTRACT HAlBEA zeolite is prepared by calcination of parent TEABEA zeolite at 823 K for 3 h in air following ionic exchange with NH4NO3 solution. NixHAlBEA zeolites are prepared by impregnation of HAlBEA with an aqueous solution of Ni(NO3)2, following a drying at 333 K to obtain NixHAlBEA. The calcination of HAlBEA and NixHAlBEA at 773 K for 3 h in air leads to the formation of C-HAlBEA and C–NixHAlBEA with appeared, for the latter, an octahedral and tetrahedral Ni(II) species incorporated in BEA framework as evidenced by XRD, DR UV–vis and XPS. Red-C-HAlBEA and red-C–NixHAlBEA are investigated as the catalysts in dehydrochlorination of 1,2-dichloroethane into vinyl chloride monomer in the presence of hydrogen at 503–523 K. Red-C-HAlBEA and red-C–Ni1.0HAlBEA show an excellent selectivity toward vinyl chloride (∼100%). Activity of HAlBEA and NixHAlBEA in the catalytic conversion of 1,2-dichloroethane strongly depends on the acidic properties of these materials and for the latter the catalytic activity depend on metal dispersion. The small Ni particles favor the dehydrochlorination of 1,2-dichloroethane to vinyl chloride. With increasing nickel particles size decreases activity of the red-C–NixHAlBEA catalysts. For these catalysts after kinetic run sintering of nickel phase is observed. Besides of carburization the nickel sintering is the main cause of red-C–NixHAlBEA deactivation. It is stronger for spent-red-C–Ni2.0HAlBEA with larger nickel particles than for red-C–Ni1.0HAlBEA containing smaller nickel particles (smaller than 5 nm).
The Journal of Physical Chemistry B, 2006