Palladium hydrogenation catalysts based on nanodiamonds and activated carbon with a metal content of 1 wt % have been studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). It has been shown that the nature of the support has an effect on the electron binding energy of palladium and the stability of metal sites formed during supporting. The resulting catalysts exhibit activity in the model nitrobenzene and cyclohexene hydrogenation reactions under mild conditions (T = 318 K; = 0.1 MPa; solvent, ethanol); the nanodiamond-based catalyst is significantly more active and efficient than the counterpart based on activated carbon.