| Microporous and mesoporous molecular sieves possess uniform pore structure, large surface area, high porosity, controllable and narrowly distributed pore sizes, unique shape selectivity, solid acidity, and ion exchangeability. These materials can be applied as supports, adsorbents and catalysts in the chemical industry. With the development of new energy technology, environmental technology and many others, microporous and mesoporous materials will have more and more applications.Microporous and mesoporous molecular sieves are normally synthesized in the presence of organic templates. The template performs as a structure-directing agent that is critical for control of the frameworks. However, the template molecules remain trapped within the frameworks and have to be removed from the pores after the synthesis. At present, the most commonly method used to remove the template is the thermal calcination under strictly controlled conditions (i.e., temperature, heating rate and atmosphere type). Although the templates can be burnt off effectively, the thermal route may cause shrinkage of the frameworks. Alternatives to the conventional calcination are desired.In the present work, we attempt to remove the template from ZSM-5, Hβ, MCM-41 molecular sieves and zirconia (C77Zr) using a novel dielectric-barrier discharge (DBD) plasma technique. The DBD plasma, which is initiated at room temperature and operated at atmospheric pressure, has been successfully applied for the template removal from materials above mentioned. The template removal rate from the molecular sieves using DBD is about eight times higher than that using the conventional thermal calcination. The thermal effect is not significant during the template removal using DBD. The experiments indicated that the shrinkage of framework structure for plasma prepared sample is less than that for thermally treated sample. Upon FT-IR analyses, the DBD plasma can lead to enhanced Br?nsted acid and Lewis acid sites. In addition, there is no hazardous reagent used during the DBD template removal. According to the present results, we would suggest that the DBD plasma technique could be a fast, facile and environmental friendly alternative to the conventional thermal calcination for the template removal. In addition, during the template removal from MCM-41, the DBD plasma patterns with characteristics of target waves were observed. The similar patterns were also observed in the presence of SBA-15 and SiO2. This is the first time that the DBD plasma patterns like this were observed. It provides a convenient model for the related subjects of plasmas.The oxidation with active oxygen species like O and O3 is important for the template removal. In addition, energetic electron bombardment resulted in the decomposition of template moleculars. The removal of activated carbon template from the C77Zr sample confirmed the oxidation mechanism of the template removal using DBD plasma.In order to confirm the effectiveness of this novel plasma template removal method, the plasma prepared and thermally calcined MCM-41 samples were tested as catalyst support. Suzuki reaction was carried out over the MCM-41 supported Pd catalysts. The plasma prepared MCM-41 supported Pd catalyst shows a slightly higher yield, compared to the calcined MCM-41 supported Pd catalyst.In this work, DBD plasma has also been successfully applied for removing the template from the HZSM-5 and decomposing the PdCl2 to PdO simultaneously. Such prepared catalyst presents a higher catalytic activity over the catalyst prepared by thermal calcination in the reaction of methane combustion. The DBD plasma method is a good method for template removal and decomposition of catalyst precursor simultaneously, which represents a simple and fast method for catalyst preparation.
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