Abstract
Here, a comparison between four mesoporous siliceous compounds is conducted to investigate the effect of support on formation and catalytic behavior of palladium (Pd) nanoparticles. The four investigated supports are: the commercially available MCM-41, SBA-15 and MCM-48, in addition to the home-made TUD-1 material. The same amount of Pd (Si/Pd = 200) was impregnated in the four mesoporous samples by using water as a solvent, and no further activation/reduction was performed. The obtained characterization data showed that SBA-15 accommodated the maximum amount of PdO nanoparticles that located inside its channels, while the maximum surface area after impregnation was obtained in MCM-48 sample. The four Pd samples was used to catalyze the solvent-free reduction of cyclopentene at room temperature by using 1 atm of hydrogen gas. Pd-TUD-1 exhibited the maximum activity with a total TOF of 4.83 s(-1), while the TOF of SBA-15 was 2.28 s(-1). The activity results clearly show the effect of the open three dimensional structure of TUD-1 in offering the maximum accessibility to and from Pd nanoparticles' active sites.