Hollow Ni–B amorphous alloy with enhanced catalytic efficiency prepared in emulsion system

Abstract

Ni–B nanospheres were synthesized through chemical reduction of nickel ions with borohydride in an emulsion system comprised of cyclohexylamine, polyethylene glycol, and water. With the characterization of X-ray diffraction, selective area electronic diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy, the resulting hollow Ni–B nanospheres were identified to be amorphous alloys with a hollow chamber. Cyclohexylamine played a significant role in fabricating hollow Ni–B nanospheres, because only solid nanoparticles were obtained in the absence of cyclohexylamine. Polyethylene glycol also had a significant influence on the formation of hollow Ni–B nanospheres, because low yield of hollow nanospheres were achieved without this polymer. During liquid-phase chloronitrobenzene hydrogenation, the as-synthesized Ni–B catalyst exhibited a much higher activity and even better selectivity than the dense Ni–B nanoparticles prepared by direct reduction of nickel ions with borohydride.