Preparation And Catalytic Activities Of Highdispersed Nanometal/Montmorillonite Composites

Nanomaterials have unique physical and chemical properties, such as quantum size effect, small size effect and surface effect, so it is received more and more attentions. Nanosized powder with higher surface energy is prone to aggregate so as to disperse difficultly, thereby their excellent nanometer characteristics are deteriorated. In order to resolving this problem, nanosized metal and semiconductor particles loading and stabilizing on layered clays and the catalytic activities of these composite materials have been studied in this thesis.In this thesis, nanosized metal/montmorillonite (MMT) and nanosized semiconductor/MMT composites with better dispersivity and thermal stability were prepared using an intercalation assembling method. And their routes of preparation, structure and catalytic activity of composites were also systematically studied.Studies indicate that a highdispersed nanosilver/MMT composite catalysts with uniform distribution of particle size of silver ranging from 30-40nm located on the platelet of exfoliated MMT was prepared, in which the MMT was used as support, the ascorbic acid as reductant, and the mixed water and ethanol as reaction resolvent. It is found that this catalyst shows an excellent catalytic degradation activity to methylene blue near room temperature. The results indicate that the catalytic activity mainly depends on the dispersivity and loading amount of nanosilver on MMT and can be kept at calcination temperatures below 200℃ that was revealed by evaluating the catalytic activity of the catalysts at different calcination temperatures together with characterizations via X-ray diffractometer(XRD), Transmission Electron Microscopy(TEM) and Atomic Absorption Spectrometry(AAS).It is found that TiO₂/pillared MMT (TiO₂/MMT) composite catalyst...