Effect of Cu Content on Structure of NiCu Alloy Catalyst and Catalytic Performance for Nitroarenes Hydrogenation

Abstract Carbon doped silica‐supported NiCu alloy nanoparticles (Ni 1 Cu x /C@SiO 2 ) with different Cu/Ni molar ratio (x=0.12, 0.24, 0.36) were fabricated via one‐step impregnation, following in situ carbonization reduction. Effects of Cu content on catalyst structure, surface properties and particle sizes were investigated by Brunauer‐Emmett‐Teller (BET), inductively coupled plasma (ICP), Raman, X‐ray diffraction (XRD), transmission electron microscopy (TEM) and X‐ray photoelectron spectroscopy (XPS). The surface Ni 0 content increased with increasing Cu content, but showed a maximum at 0.24 of Cu/Ni molar ratio, because the smaller NiCu alloy nanoparticle formed and the segregation of antioxidative Cu atoms on the surface protected the metallic Ni from oxidation. The Ni 1 Cu x /C@SiO 2 were investigated for nitrobenzene hydrogenation with H 2 . The optimal Ni 1 Cu 0.24 /C@SiO 2 catalyst with the highest Ni 0 content showed markedly improved catalytic activity compared to monometallic Ni/C@SiO 2 . The Ni 0 species were the active sites for the hydrogenation of nitrobenzene. The Ni 1 Cu 0.24 /C@SiO 2 could transform various substituted nitroarenes to corresponding aromatic amines. Moreover, the Ni 1 Cu 0.24 /C@SiO 2 could be recycled for 8 times without decrease in catalytic performance, exhibiting superior anti‐oxidation and anti‐leaching abilities.