Hydrogenation of nitrophenols catalyzed by carbon black-supported nickel nanoparticles under mild conditions

A carbon black (CB) supported nano-Ni catalyst is prepared by a facile method using nickel chloride as the nickel source and hydrazine hydrate as the reducing agent. TEM observation shows that Ni nanoparticles have a good dispersion with a narrow size distribution on the surface of carbon black. The catalyst exhibits significantly high catalytic activity for hydrogenation of nitrophenols even at 30   °C. The high performance obtained here can be attributed to the specific characteristics of the nanostructure of the catalyst and the synergistic effect of nano-Ni and carbon black, including plenty of oxygen-containing groups of carbon black for anchoring Ni atoms, strong adsorption ability for organic molecules and good conductivity for electron transfer from the carbon black to Ni nanoparticles. Moreover, the Ni-based catalyst is relatively cheap and magnetically separable, thus achieving a low-cost hydrogenation of nitrophenols to aminophenols.