Fabrication of Co(OH)2 coated Pt nanoparticles as an efficient catalyst for chemoselective hydrogenation of halonitrobenzenes

Co(OH)2 coated platinum nanoparticles Pt/Co(OH)2 were prepared by microwave assistance and hydrothermal method, and the prepared samples were composed of Pt nanoparticles with an average size of 1.8 nm coated uniformly in the thin Co(OH)2 leaves based on the results of X-ray diffraction, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The Pt/Co(OH)2 presented excellent catalytic performance in the chemoselective hydrogenation of halonitrobenzenes such as chloronitrobenzenes, bromonitrobenzene and iodonitrobenzene, and above 99.6% selectivity to haloanilines was achieved at complete conversion irrespective of the substrates used, even for iodonitrobenzene to which the dehalogenation is more easily to occur. Co(OH)2 was confirmed to prohibit the dehalogenation effectively, and the Pt/Co(OH)2 catalyst could be recycled for several times.

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► Co(OH)2 coated platinum nanoparticles Pt/Co(OH)2 have been prepared.
► The Pt nanoparticles were high dispersed and embodied into the thin leaves of Co(OH)2.
► Pt/Co(OH)2 was an efficient catalyst for chemoselective hydrogenation of halonitrobenzenes.
► Above 99.6% yield to haloanilines was achieved.
► The Pt/Co(OH)2 catalysts were stable and could be reused for several times.