Preparation And Catalytic Hydrogenation Properties Of Molybdenum Disulfide Composites Pillared By Hydroxy-Zirconium Oligocations

Molybdenum disulfide is a semiconductor, which has diverse properties such as anisotropy, electricity, magnetism, catalysis etc. MoS2 has a layered structure, and there is only the van der Waals's force between the layers. Otherwise many foreign atoms or inorganic and organic molecules (or ions) as guests have been intercalated into its interlayer galleries through synthetic methods to prepare one kind of advanced functional materials. Such materials are in possession of excellent physical and chemical properties, which are expected to make a prosperous application in the areas such as industry catalysis, environment protection and new energy exploiture.Utilizing the exfoliation and restacking properties of LixMoS2, Zr-intercalated MoS2 composites, assembled from molybdenum disulfide layers and hydroxyl-Zr oligocations, have been successfully prepared in this dissertation. Their interlayer expansions of 0.437 ~ 0.997 nm indicated that there exist two arrangement possibilities of the hydroxyl-Zr oligocations, single- and double-layer fashions, in the interlayer galleries between the host layers. By inserting polycation in to host layers, the binary metal pillared composites Al/Zr-MoS2, Fe/Zr-MoS2, Co/Zr-MoS2 and Ni/Zr-MoS2 have been prepared by a substitution reaction with different metal molar ratio. And the basal interlayer spacings for the two kinds of composites are 0.797 ~ 0.918 nm, 0.855 ~ 0.917 nm, 0.486 ~ 0.956 nm and 0.396 ~ 0.937 nm respectively. The structures and properties of the pillared composites were investigated by means of XRD, EDS, DSC, SEM, and IR etc. The results showed that the intercalates remain the original layered structure of the host. Small content of Al3+, Fe3+, Co2+ and Ni2+ cation mixed in the Zr pillaring solution can retain [Zr4(OH)16?n(H2O)8+n]n+ species (Zr4 for short). With the increasing of the secondary metal content, the hydrolyze balance of ZrOCl2 interferes, the basal interlayer spacings and the crystallinities of the pillared materials decreases gradually. Otherwise, the single metal cation, such as Al3+, Co2+ and Ni2+, can be intercalated into host layers with [Al13O4(OH)24+x(H2O)12?x](7?x)+, [Co(H2O)n]2+ and [Ni(H2O)n]2+ specieses. The liquid-phase nitrobenzene saturated hydrogenation was used as the probe reaction to examine the catalytic activities of the pillared composites. It exhibits that the catalytic activities of the pillared composites are 2 to 5 times higher than that of the pristine 2H-MoS2 under the same experimental conditions. And the conversions of nitrobenzene are enhanced in a similar trend. This fact suggests that the restacked MoS2 sheets in the layered composites be expected to have more defects than 2H-MoS2. The catalytic activities of the binary metal-pillared composites surpass those of the unitary metal-pillared ones, due to the increasing ratio of the rim active sites of them. The research also showed that the series of Zr catalysts have repetitiousness under used conditions.