A substituted imidazolate-based MOF (SIM-1) membrane has been crystallized in situ on a tubular asymmetric alumina support that can be exploited for gas separation through preferential adsorption.
The new square planar tetracarboxylate ligand L (4,4 0 ,4 00 ,4 000-(9,9 0-spirobi[fluorene]-2,2 0 ,7,7 0-tetrayl) tetrabenzoic acid) was synthesized and used for synthesis of the Metal-Organic Framework Cu 2 L (H 2 O) 2 $(EtOH) 4 denoted SBF-Cu. This material possesses the classical 4-4 regular tiling topology with paddle-wheel inorganic building units. Due to the presence of SBF cores, the interactions between the layers of this MOF confer it specific properties: high specific surface area, open metal sites under activation, and promising hydrogen uptake capacity.
The control of the atomic-scale properties of highly
dispersed
multimetallic particles represents a challenging question for the
optimal use of metallic active centers in nanoscience. In particular,
improving the formation of Pt
x
Sn alloyed
clusters on γ-alumina of a size close to 1 nm with a high Sn0/Pt ratio represents a crucial step toward more selective
heterogeneous catalysts. For that purpose, bimetallic SnPt-based and
trimetallic SnPtIn-based catalysts were prepared by surface organostannic
chemistry on monometallic Pt and bimetallic PtIn-based catalysts.
These systems were characterized by a multitechnique approach combining
CO chemisorption, temperature programmed reduction, scanning transmission
electron microscopy, Mössbauer spectroscopy, and X-ray absorption
spectroscopy. The nature of the PtSn phase in trimetallic SnPtIn-based
catalysts is found to strongly depend on the way indium is initially
introduced in the parent catalyst, by either wet impregnation or coprecipitation
with aluminum precursor. The key role of In3+ species on
the formation of PtSn alloyed clusters is revealed. By using density
functional theory calculations, we give a rational interpretation
of the experimental results and provide an atomic scale description
of Pt
x
Sn
y
/γ-Al2O3 systems, with or without In3+ on
the alumina surface. The formation of In–Pt, In–Sn,
and O–Sn bonds is indeed favored when In3+ is present
in the support. This work proposes an original approach for stabilizing
Pt
x
Sn alloyed clusters with an elevated
Sn0/Pt ratio and highly dispersed on γ-alumina using
indium as “third element” introduced as In3+ on the support.
We report the supercell crystal structure of a ZIF-8 analog substituted imidazolate metal-organic framework (SIM-1) obtained by combining solid-state nuclear magnetic resonance and powder X-ray diffraction experiments with density functional theory calculations.
-Catalytic reforming process has been used to produce high octane gasoline since the 1940s. It would appear to be an old process that is well established and for which nothing new could be done. It is however not the case and constant improvements are proposed at IFP Energies nouvelles. With a global R&D approach using new concepts and forefront methodology, IFPEN is able to: -propose a patented new reactor concept, increasing capacity; -ensure efficiency and safety of mechanical design for reactor using modelization of the structure; -develop new catalysts to increase process performance due to a high comprehension of catalytic mechanism by using, an experimental and innovative analytical approach ( 119 Sn Mössbauer and X-ray absorption spectroscopies) and also a Density Functional Theory (DFT) calculations; -have efficient, reliable and adapted pilots to validate catalyst performance.Résumé -Le reformage catalytique : méthodologie et développement procédé pour une optimisation et une amélioration constante des performances -Le reformage catalytique est utilisé pour produire des essences à haut indice d'octane depuis les années 40. Il pourrait apparaître comme un « vieux » procédé mature et pour lequel aucune innovation n'est possible. Ce n'est pourtant pas le cas, et des améliorations permanentes y sont apportées par IFP Energies nouvelles. À l'aide d'une stratégie de recherche globale, IFPEN est en mesure de : -proposer un nouveau concept de réacteur breveté augmentant la capacité ; -assurer l'efficacité et la fiabilité des designs mécaniques des réacteurs via la modélisation fine des structures ; -développer des nouveaux catalyseurs augmentant les performances du procédé grâce à une compréhension poussée des mécanismes, ceci par le couplage d'expérimentation et de techniques analytiques innovantes ( 119 Sn Mössbauer et X-ray absorption spectroscopies) et aussi par modélisa-tion moléculaire quantique ; -proposer des évaluations fiables, précises et optimisées des catalyseurs sur une gamme d'unité pilote adaptée.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.