▎ 摘　　要

The investigation on the catalysts for reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) with NaBH4 have captured intensive interest. Nevertheless, the materials with low expenditure and outstanding catalytic performances are difficult to obtain. Herein, a simple and efficient strategy, which was assisted with external magnetic field, had been proposed for preparation of graphene-coated nickel nanowires (NiNWs/G) nanocomposite magnetic catalyst. The whole fabrication procedure was facile without harsh preparation conditions like high-pressure, high-temperature, strong acid and expensive templates. The NiNWs/G could be easily and quickly prepared in aqueous solution under mild conditions, and the external magnetic force was adopted to induce the unidirectional self-assembly of metal crystals on graphene oxide to form NiNWs/G with aspect ratio more than 50. The possible formation mechanism suggesting that the nanoparticles would aggregate along with direction of the magnetization axis because the dipole magnetic moments of them are in line under magnetic induction lines. The characterization results confirmed the chemical component and morphology of the nanocomposite. The ferromagnetism is determined by hysteresis loop of NiNWs/G. More importantly, the nanocomposite exhibited superior catalytic performance toward reduction of 4-nitrophenol. Therefore, such nanocomposite will be a promising candidate for water treatment and catalyst industry. [GRAPHICS]