Y.-H. Yue

Characterization and reactivity of Ni,Mo-supported MCM-41 catalysts for hydrodesulfurization

The adorption isotherms of MCM-41 molecular sieve and catalysts exhibit two regions in their reversible parts and also two hysteresis loops. The first hysteresis at relative pressure below 0.4 is assigned to the capillary condensation in the mesoporous channels, and it is sensitive to the filling or blockage in the channels. The adsorption isotherms together with XRD results can be used to characterize the dispersion of nickel and molybdenum oxides on MCM-41. MCM-41 supported Ni and Mo catalysts are in general more active than similar NaY supported catalysts, but they are more strongly dependent on the dispersion of metal oxides owing to the unidimensional channel system, of MCM-41.

High Si/Al ratio HZSM-5 supported Ga2O3: a highly stable catalyst for dehydrogenation of propane to propene in the presence of CO2

Abstract High catalytic activity and stability of dehydrogenation of propane to propene in the presence of CO2 were achieved over Ga2O3 catalyst supported on HZSM-5 with high Si/Al ratio. The propene yield stabilized at about 22 % without observable deactivation in 100 h, which was thought to be caused by adjusting the acidity of the catalyst appropriately through dealumination of the zeolite. The reaction mechanism on the titled catalyst was discussed.

Zeolite pore size engineering by chemical liquid deposition

Pore size engineering of NaY, NaZSM-5 and HZSM-5 zeolites have achieved successfully in solution using silicon alkoxides and halides as deposition agents. For NaZSM-5 and HZSM-5 zeolites SiCl4 is more effective on pore size controlling than Si(OCH3)4 and Si(OC2H5)4. The CLD zeolites display excellent shape-selectivity for separation of various industrially interested organic isomer mixtures.

H3PW12O40 AND ITS CESIUM SALTS AS PENTANE ISOMERIZATION CATALYSTS AT AMBIENT TEMPERATURE

H3PW12O40 and its acidic cesium salts are catalytically active for pentane isomerization at ambient temperature. The influence of activation temperature and Cs content of the catalysts on their activity and selectivity have been investigated and discussed in relation to textural properties and surface acidity. H3PW12O40 and Cs2.25H0.75PW12O40 are superacidic as evaluated by measuring the rate constants of pentane isomerization at 35°C. Their acid strengths are in the range of H0=−13∼−12.4.

Synthesis and functionalization of mesoporous zirconium (IV) phosphate-phenylphosphonate with small mesopores

Abstract The synthesis and functionalization of mesoporous zirconium (IV) phosphate-phenylphosphonate have been systematically described as a new non-siliceous mesoporous material. The mesostructure formation and functionalization could be proved through XRD, BET, 31 PMASNMR, IR, TEM and TGA characterization methods. The samples prepared have worm-like 3D-connected tubular mesopores, higher surface areas and better thermal stabilities in contrast to the layered analogs. The amount of phenyl groups inside the samples could be adjusted by controlling the molar ratio of the phosphoric and phosphonic acids during the synthesis procedure. Furthermore, the phenyl groups inside the pore channels of samples can be easily functionalized through phenyl substitution reactions to incorporate sulphonate, bromic, nitro groups. After functionalization, the sulphonated and brominated samples still kept the mesostructure but the nitrified sample did not. The results of the NH 3 adsorption microcalorimetric and TGA measurements demonstrated that the sulphonated sample had more strong acid sites and higher thermal stability, and consequently possess higher acid catalytic activity for the liquid phase esterification reaction between benzoic acid and methanol.