Papers by Author: Shuang Xi Liu

Abstract: A new organic silicane which is bridged by a long amino-functionalized alkyl chain was prepared and used as the precursor in the synthesis of a series of PMO materials. The organic silicane was added into the reaction system in CH₂Cl₂ and the PMO materials were prepared by a simple stirring method under acidic condition, with a nonionic surfactantBrij 76 as template. To find the proper synthesis condition, the time of stirring and the proportion of organic silicane and TEOS were varied. Liquid and solid state NMR, X-ray diffraction (XRD) patterns, thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and N₂-physisorption properties were used to characterize the structures.

Abstract: Zeolites mordenite (MOR) and β decorated with high dispersion degree and loading content of CuO composite (symbolized as CuO/zeolite) were prepared via a novel method-the stepped hydrothermal synthesis. The resultant composite were characterized with details by powder XRD, ICP-AES, H₂-TPR and TEM techniques. Shown by experiment, the stepped hydrothermal synthetic method adopted in the present research using urea as alkali source as well as benefiting from the ultrasonic wash treatment hardly damages the zeolitic framework structure. Compared with ammonia, high dispersion degree and loading level of CuO are yielded as a consequence of the employment of urea as alkali source. Besides, the ultrasonic wash treatment not only removes some CuO precursors that deposit on the external surface of the porous support but also produces a uniform distribution of CuO particles with smaller dimension on the surface of zeolites: CuO are dispersed in nanoscale of about 4-8 nm on mordenite and 2-5 nm on zeolite β. The present synthetic strategy could be therefore applied as a novel general method for the manufacture of functional materials in a wide spectrum.

Abstract: In this paper a novel strategy that aimed to coordinate the hydrolysis rates of different silanes was used to prepare PMOs. Attribute to the organic precursor released from the CH₂Cl₂ phase, the hydrolytic process of organosilane was obviously changed in the water-surfactant system. Consequently, the hydrolysis rates of different silanes do well match in a macroscopic level. These PMO materials were characterized by TEM and powder XRD. All the results indicated that large organic functionalized PMO materials with highly ordered hexagonal mesostructure and high loading of organic species were successfully prepared, while the ²⁹Si MAS NMR experiment proved the organic species had been incorporated into the framework.