In
the area of catalysis, selective reduction of nitro compounds
to amino compounds is a colossal challenge due to the existence of
competitive reducible functional groups. Herein, an Fe-based catalyst
FeSAs/Fe2O3ACs/N-doped polyhedral
carbon (NPC) has been designed and synthesized. As we expected, compared
with FeSAs and FeNPs, FeSAs/Fe2O3ACs/NPC shows excellent catalytic performance
(turnover frequency up to 1923 h–1, calculated with
nitrobenzene), chemoselectivity, and tolerance during the hydrogenation
reaction of nitro compounds under room temperature because of the
synergistic effects between FeSAs and Fe2O3ACs. The theoretical calculations show that FeSAs prefers to undergo hydrazine decomposition to generate hydrogen
and the Fe2O3ACs surface is more active toward
the nitrobenzene reduction to aniline.
Herein, we designed and prepared a novel Fe/Fe2O3‐based catalyst, in which a remarkable synergistic effect has been revealed between Fe and Fe2O3 encapsulated in N‐doping porous carbon. The Fe‐based catalysts were fabricated via pyrolysis a mixture of MIL‐101(Fe) and melamine. The catalyst exhibits exceptionally high catalytic activity (TOFs up to 8898 h−1 which is about 100 times higher than the similar kinds of catalysts) and chemoselectivity for nitroarene reduction under mild conditions.
Synergistic effects of multimetallic catalysts play a crucial role in the field of heterogeneous catalysis, especially in the oxidation and reduction of functional groups. Hence, how to design a multimetallic catalyst with high catalysis performance attracts the attention of scientists. Herein, we have designed and synthesized a cobalt−nickel bimetallic catalyst step by step. More interestingly, the cobalt−nickel nanoparticles were encapsulated in N-doped hollow porous carbon (HPC), on which were grown many carbon tubes. The optimized nanoparticle as a hydrogenation catalyst exhibits superior performance in the selective reduction of quinoline at ambient temperature, due to its advantage of dispersing uniform bimetal nanoparticles and Ndoped active sites.
Herein, a series
of Fe-based catalysts have been designed and prepared by grinding
a mixture of MIL-88d and melamine, and then the mixture was followed
by pyrolysis. An unusual Fe/Fe3C-activated site is uniformly
encapsulated in the N-doped carbon tubes obtained by pyrolysis of
the film-like nanocrystals of MIL-88d. Experimental characterizations
and theoretical calculations demonstrate that the surface N sites
can effectively trap the nitrobenzene and aniline by their phenyl
groups with the formation of three C–N bonds that made the
catalyst exhibit excellent catalytic activity (turnover frequencies
of ≤11268 h–1 calculated on the basis of
nitrobenzene) and chemoselectivity for the reduction of nitro derivatives
under facile conditions.
The hydrogenation of nitrogen‐containing heterocyclic precursors in aqueous medium is quite challenging, especially at low temperature and without imposing molecular hydrogen pressure. In the light of the edges of metal nanoparticles (NPs) possess high selective activity, but most of the exposed metal surface does not. Hence, to influence the activity of the entire NPs surface, the use of zeolitic imidazolate frameworks (ZIFs) to obtain the metal NPs encapsulated in the carbon tubes which has been applied frequently. Herein, we design and synthesize a series of metal catalysts encapsulated in N‐doped carbon nanotubes (NCT), which disperse on the hollow N‐doped carbon framework (HNC), via pyrolysis ZIF‐67, ZIF‐67@ZIF‐8, and ZIF‐8@ZIF‐67 step by step. The catalyst of Co@NCT/HNC shows outstanding activity of hydrogenation of quinoline under mild conditions, due to the synergistic effects between Co NPs, NCT and HNC, such as the NCT make the hydrogen reach the surface of the reactant rapidly, and the encapsulated structure can enormously prevent the metal aggregating.
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