溶胶—凝胶伴随相分离法制备氧化锆基多孔块体的研究

发布时间：2018-05-27 05:33

本文选题：溶胶-凝胶 + 相分离　；参考：《浙江大学》2016年硕士论文

【摘要】：氧化锆基多孔材料兼具有氧化锆基材料低热导率、高热稳定性以及多孔材料比表面积高、隔热性好和吸附性好等特点,可广泛用于催化、分离、隔热等领域。本文综合论述了氧化钇稳定氧化锆、锆酸镧和锆酸钡三种氧化锆基材料的研究现状,采用溶胶-凝胶伴随相分离法制备了氧化钇稳定氧化锆、锆酸镧以及错酸钡多孔块体材料,重点分析了相分离诱导剂、凝胶促进剂、溶剂组成以及热处理温度对样品微观形貌和多孔结构的影响。制备出的具有共连续骨架、贯通大孔结构氧化锆基多孔材料,为氧化锆基多孔材料的应用奠定了重要基础。主要研究内容和结果如下：(1)以廉价的氯化物无机盐氧氯化锆、氯化钇为前驱体,乙醇和去离子水的混合溶液为溶剂,聚氧化乙烯为相分离诱导剂,乙二醇为络合剂,甲酰胺为干燥控制化学添加剂,环氧丙烷为凝胶促进剂,采用溶胶-凝胶伴随相分离法制备氧化钇稳定氧化锆多孔块体材料。40℃条件下凝胶反应得到的湿凝胶经过常压干燥后可以得到具有共连续骨架的氧化钇稳定氧化锆多孔块体。相分离后,相分离诱导剂主要分布在液相中,体系熵的减小是相分离的主要驱动力。钇的掺杂量对于凝胶微观形貌影响不大,掺杂0.094～0.337g氯化钇得到的样品都拥有理想的共连续骨架,样品的平均大孔孔径为1.7μm左右,且孔隙率均超过60%。热处理后,钇掺杂的氧化锆多孔块体没有出现单斜相氧化锆晶型,钇的掺杂能够对氧化锆的晶体结构起到稳定化作用；掺杂0.264 g氯化钇得到的样品经800℃热处理后,平均大孔孔径因为烧结作用减小至0.7μm,样品的比表面积也由287m2·g-1降低至34 m2·g-1。(2)以氧氯化锆、氯化镧为前驱体,乙醇和去离子水的混合溶液为溶剂,聚氧化乙烯为相分离诱导剂,乙二醇为络合剂,甲酰胺为干燥控制化学添加剂,环氧丙烷为凝胶促进剂,采用溶胶-凝胶伴随相分离法制备锆酸镧多孔块体材料。通过优化原料比例得到的湿凝胶,在进行溶剂置换后常压干燥,可以得到具有共连续骨架的锆酸镧多孔块体。样品干凝胶1100℃热处理后能够得到F-结构的锆酸镧,提高热处理温度F-结构锆酸镧向P-结构锆酸镧转变；热处理后得到的样品中仍含有少量氧化锆。采用该方法得到的锆酸镧块体热处理前孔隙率为55%,1100℃热处理后样品孔隙率上升至69%,但热处理前后的样品比表面积都相对较低。(3)以氧氯化锆、氯化钡为前驱体,乙醇和去离子水的混合溶液为溶剂,聚氧化乙烯为相分离诱导剂,甲酰胺为干燥控制化学添加剂,环氧丙烷为凝胶促进剂,乙二醇为络合剂,采用溶胶-凝胶伴随相分离法制备锆酸钡多孔块体材料。通过调整相分离诱导剂和凝胶促进剂的用量,可以制备出具有理想共连续骨架、平均大孔孔径为1.8μm、孔隙率高达63%的锆酸钡多孔块体材料。1100℃热处理后,样品中出现通过固相反应生成的锆酸钡晶型；热处理后样品大孔结构变化不大,样品平均孔径为1.5μm,孔隙率为65%,但样品比表面积由热处理前188m2·g-1降低至0.8 m2·g-1。
[Abstract]:Zirconia based porous materials have the characteristics of low thermal conductivity, high thermal stability, high thermal stability, high surface area, good heat insulation and good adsorbability, and can be widely used in catalysis, separation and heat insulation. This paper deals with the research of three zirconia based zirconia, lanthanum zirconate and barium zirconate. Yttrium oxide stabilized zirconium oxide, lanthanum zirconate and barium silicate porous block materials were prepared by sol-gel adjoint phase separation method. The phase separation inducer, gel promoter, solvent composition and the effect of heat treatment temperature on the micromorphology and porous structure of the sample were emphatically analyzed. The co continuous skeleton and through macroporous structure were prepared. The zirconia based porous material has laid an important foundation for the application of zirconia based porous materials. The main research contents and results are as follows: (1) using the cheap chloride inorganic salt and oxygen zirconium chloride, yttrium chloride as the precursor, the mixed solution of ethanol and deionized water as the solvent, the polyethylene oxide as the phase separation inducer, the ethylene glycol as complexing agent, formyl Amine is a chemical additive for drying control, and the epoxy propane is a gel promoter. The porous yttrium oxide stabilized zirconia porous block material is prepared by the sol-gel accompanying phase separation method. The gel reaction obtained by the gel reaction under the condition of the gel reaction can get the porous yttrium stabilized zirconia porous block with CO continuous skeleton after the gel reaction. Phase separation can be obtained. The phase separation inducer is mainly distributed in the liquid phase. The decrease of the system entropy is the main driving force of the phase separation. The doping amount of yttrium has little effect on the micromorphology of the gel. The samples doped with 0.094 ~ 0.337g yttrium chloride have an ideal co continuous skeleton, the average pore size of the sample is about 1.7 mu, and the porosity is more than 60%. heat. After treatment, the yttrium doped zirconia porous block has no monoclinic zirconia crystal. The doping of yttrium can stabilize the crystal structure of zirconia; the average pore size of the sample doped with 0.264 g yttrium chloride is reduced to 0.7 m after the heat treatment at 800 C, and the specific surface area of the sample is also 287m2. G-1 It is reduced to 34 m2. G-1. (2) with zirconium oxychloride, lanthanum chloride as precursor, mixed solution of ethanol and deionized water as solvent, polyethylene oxide as phase separation inducer, ethylene glycol as complexing agent, formamide as the chemical additive for drying control, epoxy propane as gel promoter, and preparation of lanthanum zirconate porous block by sol-gel adjoint phase separation method The porous lanthanum zirconate block with CO continuous skeleton can be obtained by drying the wet gel obtained by optimizing the proportion of raw materials. The sample dry gel can get F- structure lanthanum zirconate after heat treatment at 1100 C, and improve the heat treatment temperature F- structure lanthanum zirconate to P- structure lanthanum zirconate. After heat treatment, the heat treatment can be obtained. A small amount of zirconium oxide was still contained in the sample. The porosity of the lanthanum zirconate block before heat treatment was 55%, the porosity of the sample increased to 69% after heat treatment at 1100 C, but the surface area of the sample before and after heat treatment was relatively low. (3) zirconium chloride, barium chloride were used as the precursor, and the mixed solution of ethanol and deionized water was used as solvent. Ethylene oxide is a phase separation inducer. Formamide is a chemical additive for drying control. Epoxy propane is a gel promoter and ethylene glycol is the complexing agent. Barium zirconate porous block material is prepared by sol-gel adjoint phase separation method. The ideal co continuous skeleton can be prepared by adjusting the dosage of phase separation inducer and gel promoter. After heat treatment at.1100 C, the average pore size is 1.8 u m and the porosity is up to 63%. The sample appears barium zirconate crystal formed by solid state reaction. The macropore structure changes little after heat treatment, the average pore size is 1.5 mu m and the porosity is 65%, but the surface area of the sample is reduced to 188m2. G-1 before heat treatment. 0.8 m2. G-1.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ174.1

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