Ni@Pd core–shell nanoparticles immobilized on yolk–shell Fe₃O₄@polyaniline composites as a highly efficient, magnetically separable and atom‐economical catalyst for reduction of nitrobenzenes

Abstract

The preparation of Ni@Pd core-shell nanoparticles immobilized on yolk-shell Fe 3 O 4 @polyaniline composites is reported. Fe 3 O 4 nanoclusters were first synthesized through the solvothermal method and then the SiO 2 shell was coated on the Fe 3 O 4 surface via a sol-gel process. To prepare Fe 3 O 4 @SiO 2 @polyaniline composites, polyvinylpyrrolidone was first grafted on to the surface of Fe 3 O 4 @SiO 2 composites and subsequently polymerization of aniline was carried out via an ultrasound-assisted in situ surface polymerization method. Selective etching of the middle SiO 2 layer was then accomplished to obtain the yolk-shell Fe 3 O 4 @polyaniline composites. The approach uses polyaniline (PANI) conductive polymer as a template for the synthesis of Ni@Pd core-shell nanoparticles. The catalytic activity of the synthesized yolk-shell Fe 3 O 4 @PANI/Ni@Pd composite was investigated in the reduction of o-nitroaniline to benzenediamine by NaBH 4 , which exhibited conversion of 99% in 3 min with a very low content of the catalyst. Transmission electron microscopy, X-ray photoelectron spectroscopy, TGA, X-ray diffraction, UV-visible, scanning electron microscopy, X-ray energy dispersion spectroscopy and FT-IR were employed to characterize the synthesized nanocatalyst.

Alternative Recovery and Valorization of Metals from Exhausted Catalytic Converters in a New Smart Polymetallic Catalyst

“…The most relevant problem in the reduction of nitroarenes containing other reducible functionalities is selectivity ,. Great efforts have been made to seek highly selective catalysts for the preferential hydrogenation of the nitro group as functionalized anilines are intermediates for industrially important products and fine chemicals ,. Met x ‐EPS contains metals capable, in principle, to reduce both the nitro and the carbonyl group; therefore we tested the catalytic system in the hydrogenation of 4‐nitro‐benzaldehyde ( 17 ) (Scheme , Table ).…”

Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

“…Selective hydrogenation of aromatic nitro compounds by metal nanoparticles have seen remarkable growth in recent years , we also investigated the hydrogenation of aromatic nitro compounds over PFILs modified Ir NPs. As shown in Table , with the superior [BMIM][tppm] modified Ir NPs 1 as the catalyst, almost all the substrates could be efficiently converted into the corresponding substituted amino aromatic compounds under mild conditions except substrates with a methoxy substituent (Table , entries 7‐8).…”

Synthesis of a yolk/shell Fe3O4@poly(ionic liquid)s-derived nitrogen doped graphitic porous carbon materials and its application as support for nickel catalysts

“…[25][26][27][28] Recently, PILs have also gained considerable attention as novel carbon precursors. 18,[26][27][28][29][30] Due to our interest in the development of catalysts for useful new synthetic methodologies, [31][32][33][34][35][36] as well as the general importance of this issue, herein, we report the synthesis and characterization of yolk/shell Fe 3 O 4 @poly(ionic liquid)s-derived nitrogen doped graphitic porous carbon material, and its application as support for nickel catalysts. Recently, we reported a catalyst for the dehydrogenation of sodium borohydride and hydrogenation of nitriles.…”