The assembling forms of active phases in Pd/SBA-15(ad) and MoO3/SBA-15 catalyst samples, prepared via adsorption-reduction and impregnation-reduction, respectively, were characterized by N-2 physisorption measurement. Based on N-2 adsorption-desorption isotherms, it was speculated that the palladium,species in Pd/SBA-15(ad) exist as nanoparticles, whereas the MoO3 species in MoO3/SBA-15 are layered dispersed on the wall within the SBA-15 channels. These speculations were further confirmed by HR-TEM observation. The SBA-15 confined uniform Pd nanoparticles were efficient for solvent-free aerobic oxidation of benzyl alcohol.