| The spring up of green chemistry provides an effective means for the solving of environmental problems and the sustainable development of economics and society. The ideal green technology requires the avoidance of exhaust gas, liquid and residues and treatment from the headstream on the basis of science and technology. The goals that petrochemical technology pursues are atom economy, high selectivity and zero emission. On the other hand, using gasoline and diesel fuel with ultra-low even zero sulfur content can reduce the production of pollutants and avoid the corrosion of the apparatus and the poison of the catalysts, which also in accordance to the demand of green chemistry. To achieve the above demands, the key is to develop new effect catalytic materials and desulfurization adsorbents for gasoline and diesel fuels. The rapidly quenched skeletal Ni samples (RQ Ni) to be studied in this thesis are such a category of catalysts that satisfies the above requirements.RQ Ni is a new kind of skeletal nickel prepared by incorporation of rapid quenching technique in the preparation of Raney Ni. That is, first solidify the melt of Ni-Al alloy with a cooling speed of 106 K·s-1, then the aluminum in the alloy was extracted by alkaline leaching, resulting in the porous rapidly quenched skeletal Ni. In this thesis, systematic characterizations are carried out over the RQ Ni samples. Their activity, selectivity, thermal stability and the adsorptive desulfurization property are tested. The relationship between the structure of RQ Ni and desulfurization ability is explored. The influences of the preparation parameters of the alloy, the leaching conditions, the modification methods on RQ Ni are also investigated. The studies show that RQ Ni retains some features of Raney Ni, such as high surface area and large pore volume. Furthermore, as compared to Raney Ni, RQ Ni has more uniform composition, more crystal defects, higher solid solubility, better heat and corrosion resistance abilities. It is found that by using rapid quenching techniques, the distancebetween adjacent nickel atoms in RQ Ni can be adjusted, thus the matching between the active sites and the reactant molecules can be readily tailored and the reaction activity and selectivity can be controlled. In comparison with Raney Ni catalysts that are widely used industrially, the RQ Ni catalysts exhibit higher activity, selectivity and thermal stability. At the same time, compared with rapidly quenched alloys, it also has larger BET surface area and there is no need to pretreat before usage. It also exhibits fairly large sulfur volume and high ultimate degree of desulfurization.1. Characterization and catalytic behavior of the RQ Ni catalystRQ Ni5oAl5o alloy, with the same composition of Raney Ni-Al alloy which is widely used in industry, was prepared by using the rapid quenching technique. After being leached, RQ Ni50 catalyst was obtained. It is found that as the cooling speed is as high as 106 Ks'1 in the preparation of Ni-Al alloy, the advance of the liquid-solid interface is so fast that it depresses the long-range diffusion of atoms and consequently the formation of the phases with composition substantially deviating from the alloy average composition, e.g. the eutectic. In addition, the supercooling condition inhibits the enrichment of aluminum over the surface of the RQ NisoAlso alloy. Compared with Raney Ni, RQ Niso catalyst after alkaline leaching has residual M2AI3 phase, higher Al content, average pore diameter and porosity, lower BET surface area, larger mean crystallite size, unit-cell parameter and unsaturated degree of coordination, and more uniform active site. The residual N12AI3 phase stabilizes the skeleton and inhibits the collapse of the pores. However, the increment of crystallite size is more obvious for RQ Ni. It is possible that as there is deformation in Ni lattice, the Ni crystallites in RQ Ni are less stable and easier to aggregate. Experiments reveal that in the hydrogenation of 14 organic compounds, RQ M50 catalyst exhibits superior activity and selectivity. The turnover frequencies (TOF) of RQ Niso catalyst are 30 290% higher than those of Raney Ni and the initial selectivities over RQ Ni50 catalyst exceed 80%. This is closely related to the Al content, pore structure, crystallite property and the adsorption state of the RQ Ni50 catalyst.Studies reveal that there are many differences between Raney Ni and RQ Niso, which are caused by the different cooling speed of the Ni-Al alloy. By changing the cooling speed, we obtain a series of catalysts. It is found that the cooling speed affects the remaining Al content, the pore structure, the crystallite property and the adsorption state of hydrogen in the RQ Ni catalyst. In the hydrogenation of 2-ethylanthraquinoneand cinnamaldehyde, with the increase of the cooling speed, the activity and selectivity of the catalyst is improved. The optimal yield of hydrogen peroxide and hydrocinnamaldehyde are 94.0% and 88.8%, respectively, which are much higher than those over Raney Ni (67.6% and 57.3% respectively).The composition of the Ni-Al alloy has great effect on the structure and property of the catalyst. A series of RQ Ni-Al alloys with different Al/Ni ratio have been prepared. The existence of additional oc-Al/NiAi3 phase results in the decrease of Al content in the catalyst. Thus the skeleton stability of the catalyst decreases, inducing the decrease of the BET surface area and pore volume and the increase of the pore diameter. The increase of the Al content in the alloy results in the increase of the unit-cell parameter, and thus the thermal stability of the crystallites in the RQ Ni catalyst decreased and the crystallite size increases. On the other hand, the amount of weakly-adsorbed hydrogen in the catalyst increases with the increasing of the Al content in the alloy. In the hydrogenation of 2-ethylanthraquinone and cinnamaldehyde, the increase of the Al/Ni ratio improves the selectivity of the catalyst. The selectivities of 2-ethylanthrahydroquinone and hydrocinnamaldehyde are 94.6% and 89.9%, respectively, which are much higher than those over Raney Ni (17.1% and 62.3% respectively).In the preparation of RQ Ni catalyst, besides the preparation parameters of Ni-Al alloy, the alkaline leaching conditions have great impact on the structure and property of the catalyst. We first studied the kinetics of alkaline leaching of the RQ Ni-Al alloy. For the RQ Ni alloy, the leaching process is in good agreement with a reaction-controlled shrinking core model, while the Raney Ni-Al alloy exhibits two-stage leaching kinetics. This further confirms that the composition of the RQ Ni-Al alloy is more uniform. On the other hand, we characterized the RQ Ni catalyst obtained under different leaching conditions, such as leaching time, the particle size of the Ni-Al alloy, the concentration of the NaOH solution and the leaching temperature, and used these catalysts in the hydrogenation of cinnamaldehyde. Under proper leaching conditions, appropriate amount of Al content, high BET surface area, large pore volume, small crystallite size, uniform hydrogen adsorption sites can be obtained. The unit-cell parameters obtained under different leaching conditions are similar. In the hydrogenation of cinnamaldehyde, the maximum yield of hydrocinnamaldehyde is as high as 92.7% under optimal leaching conditions.A series of Mo modified RQ Ni-Mo catalysts are prepared by melting, leachingand impregnation methods, respectively. The effects of the content of Mo and modification methods were studied. It is found that different modification methods have different promoting effects on the RQ Ni catalysts. By using the melting method, the metastable Nii6MoioAl74 phase is identified in the alloy, which can not be obtained by natural cooling method. Addition of Mo can reduce the Ni crystallite size and unit-cell parameter, and increase the unsaturated degree of coordination, the content of weakly-adsorbed hydrogen and the thermal stability of the crystallites in the catalyst. Moreover, some Mo can exist in its elemental state in the catalyst. When using the leaching method, higher Al content and BET surface area, smaller Ni crystallite size can be obtained and the thermal stability of the skeleton can be promoted. As for the impregnation method, the efficiency of Mo usage, the uniformity of the Mo species and active sites over the catalyst can be increased. Thus, RQ Ni-Mo catalyst with high thermal stability of skeleton can also be obtained. In the hydrogenation of 2-ethylanthraquinone over RQ Ni-Mo-5% catalyst prepared by impregnation method, the yield of hydrogen peroxide is improved to 100% and the hydrogenation of the aromatic ring is completely prevented, avoiding the byproduct and the loss of 2-ethylanthraquinone and reducing the consumption of hydrogen, which is a successful example for rapidly quenched Ni using in the green chemistry.2. Adsorption and reaction of organic sulfur molecules on RQ NiAs the adsorbent in the desulfurization of gasoline and diesel fuels, RQ Ni has large sulfur volume. Experiments show that after adsorption by RQ Ni, the sulfur content in gasoline can be reduced to 20 ppb, which is virtually sulfur-free. The desulfurization of thiophene on Raney Ni and RQ Niso has been investigated by means of XPS and DRIFTS. In ultrahigh vacuum (UHV), thiophene molecularly adsorbs on Raney Ni and RQ Ni50 at 103 K. At 173 K, thiophene on alumina is desorbed, while thiophene in direct contact with the metallic Ni in Raney Ni undergoes C-S bond scission, leading to metallocycle-like species and atomic sulfur. On RQ Niso, the temperature for thiophene dissociation is about 100 K higher than that on Raney Ni. The lower reactivity of RQ Niso towards thiophene is attributed to lattice expansion of Ni crystallites in RQ Ni50 due to rapid quenching. Thus, the rapid quenching technique opens a new avenue for designing metallic adsorbents with controllable bonding strength toward thiophene and the lower reactivity can simplify the regeneration of the Ni adsorbent. The existence of alumina and hydrogen blocks...
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