The decomposition of CO 2 in a dielectric packed-bed plasma reactor has been studied. It was found that the dielectric properties and morphology of packing dielectric pellets play important roles in the reaction due to their influence on the electron energy distribution in the plasma. The acid-base properties of the packing materials also affect the reaction through the chemisorption of CO 2 on basic sites of the materials. Heterogeneous reactions on the solid surfaces of the dielectric materials also play a role in the reaction, which was also confirmed through the investigation of the influence of the discharge length on the reaction. The reverse reaction of CO 2 decomposition, the oxidation of CO, was also investigated to further understand the role of dielectric materials in the plasma and their effect on plasma reactions. Both the decomposition of CO 2 and the oxidation of CO in nonpacked or dielectric packed reactors are first-ordered.

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A series of HZSM-5 catalysts modified with various loadings of aluminum fluoride (AlF3) were prepared from a mechanical mixture route. Combined characterizations of X-ray diffraction, Fourier transform infrared (FT-IR), 27Al, 29Si, 19F MAS NMR, N2 sorption, and NH3-tempeature-programmed desorption (NH3-TPD) techniques show that the structure, texture, and acidity of HZSM-5 catalysts can be adjusted with the loading of AlF3. A suitable amount of AlF3 modification (2 wt %) could increase the framework aluminum content and the surface area of HZSM-5. However, when the loading of AlF3 came to 3 wt % or more, the contrary results were obtained, which could be ascribed to the dealumination of the zeolitic framework. The catalytic activities for dehydration of methanol to dimethyl ether (DME) show that suitable amount of AlF3-modified HZSM-5 exhibited much higher activity and better stability than parent HZSM-5. The combination of “tunable” synthesis and “superior” properties is very much valuable in the academic and industry.

Ultrathin nanosheets (6–8 nm) of aluminosilicate FER zeolites have been successfully synthesized using a sole small organic ammonium (N,N-diethyl-cis-2,6-dimethyl piperidinium, DMP).