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Developing efficient, sustainable, and stable nanocatalysts continue being the struggling goal both for academia and for industrial. Carbocatalysts have attracted great attention due to high mass transfer ability, environmental sustainability and stability. Fabricating well‐defined carbonaceous nanocatalysts for heterogeneous catalysis is intensively pursuing. In this work, a newly developed economic and facile method was applied for the large‐scale fabrication of graphite sheet encapsulated magnetic carbocatalysts. The carbocatalysts was constructed via in‐situ pyrolysis of melamine‐metallo‐supramolecular polymer precursors (MMSP) under vacuum condition. The framework of MMSP was synthesized through the condensation reaction. As a proof‐of‐concept, this method was successfully applied for the fabrication of three kinds of graphite encapsulated magnetic carbocatalysts. Based on systematically optimization, the Pt−NiO‐1000@NC‐650 nanocatalyst demonstrated highly efficient and remarkable stability for the catalytic transfer hydrogenation of 4‐nitrophenol to produce corresponding 4‐aminophenol. The kinetics study of this catalytic system illustrates the reaction order is 1st for Pt−NiO‐1000@NC‐650. Furthermore, the kinetic constant (Kapp) is 1.57 min−1 and the turnover frequency (TOF) is up to 4, 268 h−1. [ABSTRACT FROM AUTHOR]

Abstract: The carbon wrapped magnetic nanosphere Fe3O4@C (∼300 nm) was prepared under simple hydrothermal conditions, and it served as the carrier of Rh nanoparticles (2‐3 nm), which acted as the highly efficient catalyst for reduction of nitro compounds, and reutilization of catalyst is convenient to achieve because the catalyst particles are magnetic. A scope of nitroarene derivatives were reduced to corresponding anilines in water, and the reactions completed in 10 min with nearly quantitative conversions and 100% selectivity. In addition, the abundant oxygen‐containing functionality on the carbon shell which can strongly binds the Rh‐NPs to offer extraordinary stability is investigated by using various techniques, including transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), X‐Ray Diffraction (XRD), and Fourier transform infrared spectrometer (FT‐IR). [ABSTRACT FROM AUTHOR]

Fabricating efficient and stable nanocatalysts for chemoselective hydrogenation of nitroaromatics is highly desirable because the amines hold tremendous promise for the synthesis of nitrogen containing chemicals. Here, a highly reactive and stable porous carbon nitride encapsulated magnetically hollow platinum nanocage is developed with subnanometer thick walls (Fe3O4@snPt@PCN) for this transformation. This well‐controlled nanoreactor is prepared via the following procedures: the preparation of core template, the deposition of platinum nanocage with subnanometer thick walls, oxidative etching, and calcination. This highly integrated catalyst demonstrates excellent performance for the catalytic transfer hydrogenation of various nitroaromatics and the reaction can reach >99% conversion and >99% selectivity. With the ultrathin wall structure, the atom utilization of platinum atoms is highly efficient. The X‐ray photoelectron spectroscopy results indicate that partial electrons transfer from the iron oxides to Pt nanowalls, and this increases the electron density of snPt nanoparticles, thus promoting the catalytic activity for the transfer hydrogenation of nitroaromatics. For the reduction of 4‐nitrophenol, the reaction rate constant Kapp is 0.23 min−1 and the turnover frequency (TOF) is up to 3062 h−1. Additional reaction results illustrate that this magnetic nanoreactor can be reused more than eight times and it is a promising catalytic nanoplatform in heterogeneous catalysis. A magnetically hollow platinum nanocage with subnanometer thin walls is developed. Due to partial electrons transferring from the iron oxides to Pt nanowalls and high atom utilization efficiency, this highly integrated nanoreactor demonstrates excellent performance for the catalytic transfer hydrogenation of varieties of nitroaromatics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A highly active catalyst for the reduction of nitro with a TOF of 12,666 h−1 for 4-NP. • The catalyst is stable and magnetically recoverable. • The active center is two adjoining rhodium atoms. • The activity of different Rh-containing catalysts is precisely predicable. Abstract A magnetically separable 2D Rh/Fe 3 O 4 /g-C 3 N 4 -N catalyst has been synthesized for the catalytic transfer hydrogenation of nitroarenes to afford corresponding anilines. The highly dispersed Rh nanoparticles are the dominant active species. The reaction is second order for rhodium according to the kinetic study, and this means the activity of different Rh-containing catalyst can be precisely predicted and the active site contains two adjoining rhodium atoms. The strong interaction between Rh and Fe 3 O 4 contributes to the catalytic performance, therefore the obtained Rh/Fe 3 O 4 /g-C 3 N 4 -N catalyst exhibits excellent catalytic activity and chemoselectivity for the reduction of various nitroaromatics, and the turnover frequencies (TOF) can reach as high as 12,666 h−1 for 4-nitrophenol. Moreover, this catalytic system is environmentally friendly because of its green solvent water and harmless byproducts (H 2 O and N 2), and the catalyst shows outstanding stability and recyclability with at least 12 cycles. [ABSTRACT FROM AUTHOR]

Chemoselective hydrogenation of nitrostyrene to aminostyrene still faces the trouble of low selectivity and poor activity. The bimetallic catalysts, which adjust the activity of noble metal nanoparticles through the doping of non-noble metals, are promising for selectively catalytic transfer hydrogenation (CTH). For another aspect, the hydrogen source also plays a vital role in selective CTH. Based on this, we prepared activity-inhibited bimetallic RhIn/ZIF-8 catalyst to study the catalytic performance towards different hydrogen sources (N 2 H 4 ·H 2 O, NaBH 4 , NH 3 ·BH 3 and H 2) and to explore the natural selectivity of these hydrogen sources. We found that the hydrazine hydrate was the most selective H-donor for the nitro group, while the H 2 had the highest natural selectivity to olefins. The H 2 produced from hydrazine hydrate is responsible for the formation of completely reduced products. The potential reduction by the intermediate imine did not occur to C C double bonds, this indicates controlling the decomposition of N 2 H 4 will enhance the selectivity of nitroarenes. Based on this, the reaction system with the catalyst bimetallic RhIn/ZIF-8 and N 2 H 4 ·H 2 O as the hydrogen source is established, which can fully reduce many nitrostyrenes with >98% selectivity to corresponding aminostyrenes. [Display omitted] • Exploring the intrinsic selectivity of different hydrogen sources. • The reduction of the nitro group by the imine intermediate is excluded. • Inhibiting the decomposition of hydrazine hydrate is a key factor to ensure the selectivity of this card. • Developing a catalytic reaction system with selectivity >99% with the help of the above rules. [ABSTRACT FROM AUTHOR]