【作者】 许本静；

【导师】 阎子峰；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2007， 博士

【摘要】 在本文中,采用了诸如葡萄糖、蔗糖和淀粉等糖类分子为模板合成介孔氧化铝,并且考察了pH值、物料比、成胶温度等因素对产物结构性能的影响,还考察了表面活性剂的加入对最终产物的影响。采用诸如X射线衍射、热分析、透射电子显微镜、固体核磁共振和氮气吸脱附等手段对所得产物进行分析表征。不同糖类分子为模板合成结果表明,以葡萄糖、蔗糖、淀粉以及β-环糊精等糖类分子为模板剂均能合成出介孔氧化铝。但各种糖类分子的尺寸对合成产物的比表面积、孔体积、孔径尺寸及其分布等性能有一定影响。不同影响因素的考察表明,体系的pH值、物料中的水量和模板剂用量、成胶温度等对合成产物的物理化学性能有一定影响。不同种类表面活性剂的加入合成结果表明,各种表面活性剂(P123,CTAB,SDS)都会造成产物的性能发生变化,共同点是随着其加入量的增大,产物的孔径尺寸均增大,孔径分布变宽;不同点是P123的加入能得到双孔分布的产物,而CTAB和SDS的加入则不能得到双孔分布的产物。同时,根据离子型表面活性剂和非离子表面活性剂作用的不同,提出了两种不同的双模板作用机理,前者属于协同包覆作用机理,后者属于双模板作用机理。采用硝酸铝或酸碱配对的铝物种为铝源,以糖类分子为模板剂能合成出介孔氧化铝产物,并且其性能分别受体系pH值和物料比的影响较大。本文采用溶胶-凝胶法一步合成了镍负载介孔氧化铝催化剂和镍负载氧化锆-介孔氧化铝催化剂,XRD和TEM结果证明活性组分在载体上有较好的分散,紫外可见光吸收光谱表明,活性组分的配位状态与浸渍法所得催化剂有所不同,程序升温还原(TPR)结果表明活性组分组载体作用也与浸渍法所得催化剂有所不同。将它们应用于甲烷二氧化碳重整反应,发现这两种催化剂都具有较好的反应活性和稳定性,反应生成的积炭主要为碳纳米管,不会导致催化剂失活。更多还原

【Abstract】 In this paper, mesoporous alumina was synthesized using saccharide compounds as templates. The influence of pH value, the amounts of H2O and template, temperature and stirring time was investigated, and the effect of the adding of surfactant was also examined. The products were characterized using X-ray diffraction (XRD), thermal analysis, transmission electron microscopy (TEM), MAS NMR and N2 sorption methods.Mesoporous alumina can be obtained using glucose, sucrose, starch andβ-cyclodextrin as structure-directing templates, and the molecular size of the templates has a great effect on the physical properties of products, and the templating formation mechanism was tentatively postulated.The properties of products were influenced by the initial pH value of the system, but no obvious trend was found; Surface areas, pore volumes and pore diameters increased with the increase of temperature and the amount of H2O or glucose, and then kept stable. But the properties of products were hardly affected by stirring time.The adding of different kinds of surfactants to the system has a significant influence on the properties of products, which indicated that surfactant and glucose interact with each other. The pore size and distribution of product were increased after the addition of surfactant. Mesoporous alumina with double-size pore distribution could be produced after the addition of nonionic surfactant (P123), at the same time, the pore volume of product could also be increased sharply. The bi-templating mechanismof glucose and P123 and synergetic enwrapping templating mechanism of glucose and ionic surfactants were proposed.Mesoporous alumina can be prepared using Al(NO3)3 and‘acid-base pair’aluminum species as aluminum source in the presence of saccharide compounds. For Al(NO3)3 as aluminum source, the molecular size of templates and pH value play an important part in the properties of products. For‘acid-base pair’aluminum species as aluminum source, the ratio of acid and base aluminum species plays a great role in the properties of product.Mesoporous Ni/Al2O3 and Ni/ZrO2/Al2O3 catalysts with high surface areas were prepared using glucose as template. XRD and TEM results showed that nickel phase was uniformly dispersed on the support. These catalysts were also characterized by nitrogen adsorption-desorption, UV-vis specrtra and TPR. These catalysts exhibited good activity and marked stability in methane dry reforming.更多还原