Ultrafine palladium nanoparticles supported on mesoporous silica: An outstanding catalytic activity for hydrogen production from dodecahydro-N-ethylcarbazole

SBA-15 was treated to form a negatively charged silica surface (-Si-O-) with alkali. The ultrafine Pd nanoparticles (Pd NPs) supported on SBA-15 (Pd/SBA15) were prepared via the NaBH4 reduction of (-Si-O-)2Pd2+ formed by ionic adsorption between -Si-O- and Pd cations. The as-prepared Pd/SBA15 has showed an outstanding catalytic performance for dehydrogenation of dodecahydro-N-ethylcarbazole (H12-NEC). The dehydrogenation efficiency reached 98.27% for 1 h at 180 degrees C and 96.15% for 3 h at 165 degrees C, which was much higher than that reported in literature. Pd/SBA15 catalysts were characterized by XRD, TEM, FT-IR, XPS, N2 physical adsorption-desorption and H2 chemisorption. The results showed that Pd NPs were uniformly dispersed on pore surface of SBA-15 with high Pd dispersion of 57%. The Pd NPs was too fine to be detected by TEM. The ionic adsorption of -Si-O- and Pd cations prevented agglomeration of nanoparticles. The coordination of Pd NPs with hydroxyl on the surface of SBA-15 improved catalytic stability. The apparent activation energy of Pd/SBA15 catalyst was 74.23 KJ/mol.

Automated summary

A negatively charged silica surface (-Si-O-) was formed on SBA-15 by treating it with alkali, and ultrafine Pd nanoparticles (Pd NPs) were supported on SBA-15 via NaBH4 reduction. The as-prepared Pd/SBA15 catalyst exhibited excellent catalytic performance for dehydrogenation of H12-NEC. Characterization results revealed that Pd NPs were uniformly dispersed on the pore surface of SBA-15 with high Pd dispersion, and the coordination of Pd NPs with hydroxyl on the SBA-15 surface improved catalytic stability.