Mesoscopically spherical Ni-B amorphous alloy nanoparticles were prepared through self-assembly of an ionic surfactant hexadecyltrimethylammonium bromide. During liquid-phase nitrobenzene hydrogenation, the as-prepared mesoporous Ni-B catalyst exhibited higher activity and selectivity than the regular Ni-B obtained via direct chemical reduction, apparently owing to the higher surface area, which ensured high dispersion of active sites and the mesoporous channels that might facilitate diffusion and adsorption of reactant molecules. (c) 2006 Elsevier Inc. All rights reserved.