Ultrasound-assisted preparation of a novel Ni–B amorphous catalyst in uniform nanoparticles for p-chloronitrobenzene hydrogenation

Uniform Ni–B amorphous alloy nanoparticles were prepared by ultrasound-assisted reduction of Ni(NH3)62+ with BH4- in aqueous solution and the particle size was controlled by adjusting the ultrasound power. During liquid-phase p-chloronitrobenzene hydrogenation, the as-prepared Ni–B catalyst exhibited much higher activity and better p-chloroaniline selectivity than the regular Ni–B obtained via direct reduction of Ni2+ with BH4-. The higher activity could be attributed to both higher dispersion of Ni active sites and higher intrinsic activity. The higher selectivity could be attributed to both uniform Ni–B particles with larger size and Ni active sites with higher electron density.