Synthesis and catalytic activity of composite materials TiO_2/Ti-Al-MCM-41 by chemical vapor deposition (CVD)

摘要

TiO_2/Ti-Al-MCM-41 (TAM) with high Ti content (Si/Ti=6.2) was prepared by chemical vapor deposition (CVD) of TiCl_4 on Al-MCM-41 at low reaction temperature (423 K). The sample was characterized by X-ray diffraction (XRD), N_2 adsorption/desorption, high resolution transmission electron microscopy (HRTEM) and diffuse reflectance ultraviolet-visible spectroscopy (DR UV-vis). The results showed that Ti atoms were in tetrahedral coordinated in the framework of Al-MCM-41. Meanwhile, higher Ti~(4+) ions coordination and bulk anatase titania was observed in the DR UV-vis spectra. TAM still exhibited hexagonal p6m pore architectures, large specific surface area and narrow pore distribution. Catalytic activity of TAM for polystyrene (PS) pyrolysis has been investigated. The results showed that TAM exhibited high activity for the PS pyrolysis and good selectivity to liquid hydrocarbons of C_5-C_(12) hydrocarbons.