| Chemists and chemical engineers are now focusing on researching new materials, improving catalytic efficiency and eliminating none environmental pollution. The latter two makes fundamental essentials for green chemistry. Therefore, it became crucial for scientists to develop novel catalytic materials.Amorphous alloys represent a variety of special materials with short-range ordering while long-range disordering structure which may provide pathways to the excellent catalytic properties, i.e., good anti-poisoning ability, the higher catalytic activity and selectivity in homogeneous hydrogenation of a,p-unsaturated aldehyde, the low and even none environment pollutionUp to now, in hydrogenation of furfural to furfuryl alcohol, the most commonly used catalysts are Cu-Cr dopant Cu-Cr, and Raney Ni et al. However, highly toxicity and reactor-blockage restrained wide application to Cu-Cr catalyst. No matter how high activity Raney Ni has, it could not play an important role on the mentioned industry, because of its various undesired products and environmental contamination. Therefore, the amorphous alloy, possessing excellent catalytic properties in different reaction, would be applied in hydrogenation of furfuralIn the present thesis, the ultrafine Ni-Ce-B, Co-Fe-B amorphous alloys and supported Co-B have been prepared by chemical reduction. The catalytic performance of all the amorphous alloy catalysts mentioned above was measured during liquid phase hydrogenation of furfural to furfuryl alcohol, together with the kinetic studies. The relationship between the catalyst performance and the structure of catalyst, surface electronic state of the amorphous alloy has been systematically studied based on a series of characterization of catalysts (XRD, XPS, TEM, BET, TPD) . Meanwhile, the promoting effects of the support on the thermal stability and catalytic activity of the amorphous alloy catalysts have been discussed. Furthermore, by alternating the kinds of the additives and their amount in the amorphous alloys, the modification of several admixtures on the structure of the amorphous alloy has been investigated, which could account for their promoting effect on the catalytic behaviors.The researching work in the present thesis could be summarized as follows.1. Catalyst preparation. By adding KBH4 into a solution containing (1) NiCl2 andCe(SO4)2, (2) both CoCl24H2Oand FeCl3, the ultrafme amorphous alloys of Ni-Ce-B, Co-Fe-B were prepared, which were thoroughly washed with distilled water and stored in alcohol until the time of use.Meanwhile, the Co-B/CeO2-SiO2 amorphous catalyst was prepared by impregnating the SiO2 support with Ce(NO3)3 solution, and the drying, calcinations at 773 K for 2.0 h, and adding CoCl2 aqueous into prepared SiO2, followed by drying, calcinations, and KBRt reducing. The resulting Co-B/CeO2-SiO2 sample was washed in the similar way to that mentioned above and also kept in alcohol until the time of use.2. Activity test. All the furfural hydrogenation reactions were carried out in a autoclave containing certain amount of the as-prepared catalysts, furfural and alcohol. RH2m was determined by monitoring the drop of the hydrogen pressure inside the autoclave. The conversion of the furfural and the selectivity to furfuryl alcohol was obtained according to the product analysis by gas chromatograph. All the amorphous alloy catalysts exhibited much higher catalytic activity than Cu-Cr, which was widely used in industrial process of furfural hydrogenation, showing a good potential in industrial application.3. Correlation of the catalytic performance to the structure of the catalysts.(1) The amorphous alloys usually exhibited much higher activity than their corresponding crystalline counterpart. On one hand, in viewpoint of the structural effect, this could be attributed to the unique amorphous structure (i.e., the short-range ordering but long range disordering structure), the homogeneous distribution of the active sites, and the highly coordinative installation of these acti... |
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