▎ 摘　　要

Pd nanoparticles supported on nitrogen-doped graphene (NG) were prepared as hydrogenation catalysts. Different nitrogen sources (ethylenediamine, ammonia, and urea) were employed to synthesize NG using hydrothermal treatment under mild conditions. The as-made samples were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, elemental analysis, nitrogen adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. Remarkably improved dispersion of Pd nanoparticles was observed when nitrogen was introduced into the graphene structure. These NG-supported Pd catalysts showed enhanced catalytic hydrogenation activities owing to the superior dispersion of Pd. In the hydrogenation of different olefins, perfect turnover frequencies were obtained over the NG-supported Pd catalyst with urea as the nitrogen source.