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Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts

2018, Murugesan, Kathiravan, Senthamarai, Thirusangumurugan, Sohail, Manzar, Alshammari, Ahmad S., Pohl, Marga-Martina, Beller, Matthias, Jagadeesh, Rajenahally V.

The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.

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Morphology and Microstructure Evolution of Gold Nanostructures in the Limited Volume Porous Matrices

2020, Yakimchuk, Dzmitry V., Bundyukova, Victoria D., Ustarroz, Jon, Terryn, Herman, Baert, Kitty, Kozlovskiy, Artem L., Zdorovets, Maxim V., Khubezhov, Soslan A., Trukhanov, Alex V., Trukhanov, Sergei V., Panina, Larissa V., Arzumanyan, Grigory M., Mamatkulov, Kahramon Z., Tishkevich, Daria I., Kaniukov, Egor Y., Sivakov, Vladimir

The modern development of nanotechnology requires the discovery of simple approaches that ensure the controlled formation of functional nanostructures with a predetermined morphology. One of the simplest approaches is the self-assembly of nanostructures. The widespread implementation of self-assembly is limited by the complexity of controlled processes in a large volume where, due to the temperature, ion concentration, and other thermodynamics factors, local changes in diffusion-limited processes may occur, leading to unexpected nanostructure growth. The easiest ways to control the diffusion-limited processes are spatial limitation and localized growth of nanostructures in a porous matrix. In this paper, we propose to apply the method of controlled self-assembly of gold nanostructures in a limited pore volume of a silicon oxide matrix with submicron pore sizes. A detailed study of achieved gold nanostructures' morphology, microstructure, and surface composition at different formation stages is carried out to understand the peculiarities of realized nanostructures. Based on the obtained results, a mechanism for the growth of gold nanostructures in a limited volume, which can be used for the controlled formation of nanostructures with a predetermined geometry and composition, has been proposed. The results observed in the present study can be useful for the design of plasmonic-active surfaces for surface-enhanced Raman spectroscopy-based detection of ultra-low concentration of different chemical or biological analytes, where the size of the localized gold nanostructures is comparable with the spot area of the focused laser beam.