The ordered mesoporous aluminosilicate molecular sieve （MASMS-1） stable in the high-temperature steam has been successfully synthesized from the assembly of diluted ZSM-5-type precursor with mesoporous MCM-41. The material was characterized by XRD, N2 adsorption-desorption, FE-SEM, TEM, FT-IR spectroscopy and 27A1 MAS NMR techniques. This mesoporous material shows high stability in the high-temperature steam [H2O （φ=20%） in N2 at 800 ℃ for 4 h], which might be ascribed to the synergistic effect of both thick walls containing zeolite-like five-membered ring subunits and highly condensed surface silanol groups.
The synthesis of methanol and dimethyl ether(DME) from CO hydrogenation has been investigated on Cu-based catalysts.A series of Cu/ZnO/Al2O3 catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid,followed by calcination at 450 °C.The calcination processes were monitored using thermogravimetry differential scanning calorimetry(TG-DSC).Catalysts were further characterized using N2 adsorption,scanning electronic microscopy(SEM),X-ray diffraction(XRD),N2O oxidation followed by H2 titration,and temperature-programmed reduction with H2(H2-TPR).The reduction processes were also monitored with in-situ XRD.The physicochemical properties of catalysts depended strongly on the types of precursor salts,and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area,larger exposed metallic copper surface area,and lower reduction temperature.The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures.Catalysts prepared with copper nitrate,zinc and aluminum acetates exhibited the highest catalytic activity.
