Magnetically recoverable Ni/C catalysts with hierarchical structure and high-stability for selective hydrogenation of nitroarenes.

Here we report that magnetic Ni/C catalysts with hierarchical structure can be fabricated from a mixture of nickel acetate, polyethylene glycol-200 and furfural by a one-step hydrothermal method, followed by calcination. It has been found that the calcination temperature is the key factor affecting the structure, morphology and the catalytic performance of the Ni/C catalysts. Of the as-made catalysts, the Ni/C sample calcined at 300 °C features small-size metallic Ni particles with high dispersion in the carbon matrix and a unique hierarchical structure, and has the highest rate of conversion of o-chloronitrobenzene with high selectivity to o-chloroanilines. The concerned Ni/C catalysts are magnetic due to the presence of metallic Ni particles, which makes their recovery easy after the reaction by an external magnetic field. The recovered Ni/C catalysts can be recycled at least ten times without obvious loss both in Ni loading and the catalytic performance. This kind of catalyst is also active for the selective hydrogenation of other nitroarenes to the corresponding anilines.