Synthesis of Nickel Nanoparticles Supported on Boehmite for Selective Hydrogenation of p-Nitrophenol and p-Chloronitrobenzene

Abstract

Nickel nanoparticles supported on boehmite were prepared by a modified electroless nickel-plating method and a direct reduction method. We mainly studied the catalyst synthesized by the direct reduction method. The as-prepared nickel catalyst was characterized by X-ray diffraction and high-resolution transmission electron microscopy. The catalytic behavior in selective hydrogenation of p-nitrophenol to p-aminophenol and p-chloronitrobenzene to p-chloroaniline was studied and compared with Ni–B/γ-Al2O3 catalyst prepared by incipient-wetness impregnation and Ni–B/Al2O3·xH2O catalyst synthesized by a coprecipitation method. The Ni–B/boehmite catalysts were found to be more reactive than the Ni–B/γ-Al2O3 and Ni–B/Al2O3·xH2O catalysts. The superior activity of the Ni–B/boehmite catalyst was attributed to the small Ni–B particles and large amount of structural water, which enhanced the hydrophilicity of the catalyst. The Ni–B/boehmite sample was prepared by a direct reduction method. Compared with boehmite (a), the black spheres in b represent Ni–B cluster, the Ni–B cluster is about 20 nm in diameter.