Fabrication Of Synergistic Catalysts By Layered Precursors For Selective Hydrogenation/Oxidation

Catalytic technology is the common key techonology in petrochemical,fine chemical, coal chemical and environmental chemical industries, as well as plays an important role in the economic and social progresses.Among various catalysts, heterogeneous catalysts are widely employed due to the advantages on easy separation, low corrosiveness and non-pollution. Recently, with the depletion of non-renewable fossil resources, the studies on the developments of effective heterogeneous catalyts and novel catalytic technologies attract more attentions.Multifunctional catalyst, that is also called synergistic catalyst, includes more than two kinds of active sites, resulting in the special electronic and chemical properties for the enhancement on catalytic performance.Furthermore, the composition and structure of multifunctional catalyst could be flexibly controlled in a wide range. Therefore, based on the demands of target reactions, a series of novel multifunctional catalysts with synergy between various active sites could be developed.This project carried out the researches on controllable synthesis and structure-performance relationships of multifunctional catalysts derived from layered metal hydroxides. Based on the cation-tunability and confined effect of layers, as well as the abundant surface acid and basic sites, layered metal hydroxides were simultaneously used to obtain bulk,supported and arrayed multifunctional catalysts.1. A series of MMgMn-LDH (M=Zn, Cu, Ni, Co, Fe, Cr and Ti) bulk multifunctional catalysts with the synergy between multications were synthesized by a co-precipitation method. Benzyl alcohol oxidation was chosen as the probe reation to investigate the influences from compositons of MMgMn-LDH layer on the catalytic performances. XPS,DRIFT, 02-TPD and Raman were employed to analyze the redox of Mn and M species, as well as the structure of acitive oxygen species on the surface of catalysts in alcohol oxidation to carry out the possible reaction mechanism over LDH-based catalsyts.2. A flower-like Au/NiAl-LDH supported multifunctional catalyst with the synergy between Au and Ni species was synthesized and pretreated in 02. By the comparison between pretreated and unpretreated catalysts in benzyl alcohol oxidation, the influences on reactant activation and active species migration from Ni and Au species were explored. Furthermore,SEM, BET and MIP were carried out to investigate the relationship between hierarchical pores and catalytic performance of flower-like Au/NiAl-LDH.3. A series of Pd/NiO/Al arrayed multifunctional catalysts with the cooperation of multimetals and acid/basic sites were fabricated on the substrate of ?-ring shaped aluminum foil for anthraquinone hydrogenation. The synergistic effect between Pd NPs and acid/basic sites on the adsorption and activation of anthraquinone molecules was investigated by the comparison of support surface structures before and after hydrogenation reaction. Moreover, by SEM, HRTEM and MIP, the effect of pore structure on mass transfer performance was revealed over Pd/NiO/Al catalysts.