CHARACTERIZATION AND CATALYTIC PROPERTIES OF MCM-41 AND PD MCM-41 MATERIALS/

Pure silica MCM-41 mesoporous molecular sieve material was synthesised and characterised by in situ synchrotron XRD, TEM, TGA/DTA and DRIFTS techniques. In situ energy dispersive XRD (EDXRD) confirmed the exact nature of the pore diameter of MCM-41 and the change in crystal struc ture on calcination. The IR band at 1057 cm(-1) of as-synthesised MCM- 41 was shifted by 14 cm(-1) on heating to 673 K due to increased conde nsation of silanol groups to form Si-O-Si bridges. Calcined MCM-41 mat erials were used to support Pd, and the catalytic activities for 1-hex ene and benzene selective hydrogenation were investigated. The Pd/MCM- 41 catalyst showed high activity in hydrogenation of 1-hexene at an in let reaction temperature of 298 K, but did not show any activity in hy drogenation for benzene. TEM results for the reduced Pd/MCM-41 catalys ts revealed that the average Pd particle size was around 2-2.5 nm and these particles were located in the pores of MCM-41 and showed good di stribution. TPR measurements showed that about 70% of palladium oxide (PdO) loading in the calcined catalysts was reduced at sub-ambient tem perature.