【作者】 毛小波；

【导师】 龚茂初；

【作者基本信息】 四川大学 ， 物理化学， 2006， 硕士

【摘要】 本文对通用汽油机尾气净化三效催化剂载体及催化剂进行了深入研究。在研制出一系列不同铈锆比的稀土储氧材料和耐高温高比表面氧化铝材料的基础上,系统的研究了铈锆比对储氧材料的比表面、孔径、孔容、储氧量、铈原子利用率、热稳定性能、还原性能、结构及表面性能的影响。系统的研究了铈锆比对催化剂的起燃温度特性、空燃比、催化剂结构及热稳定性能的影响。最终研制出高性能低贵金属通用汽油机尾气净化三效催化剂。本文用共沉淀法制备了La-Al2O3和一系列不同铈锆比的储氧材料,BET测定结果表明新鲜La-Al2O3及系列新鲜储氧材料具有高的比表面、孔容、合理的孔径分布。经高温老化后,La-Al2O3表现处很好的高温热稳定性能。低铈锆比储氧材料表现出更优越的抗老化性能和更好的孔径分布。OSC及TPR结果表明,铈锆比对储氧材料的储氧量、铈原子利用率、还原性能及抗老化性能影响很大,低铈锆比材料的铈原子利用率、还原性能及抗老化性能优于高铈锆比材料,其中低铈锆比材料Ce0.35Zr0.55Y0.1O1.95表现出最佳铈原子利用率、还原性能及抗老化性能。XRD及XPS结果表明,储氧材料的铈原子利用率、储氧性能及还原性能受材料晶格缺陷的影响很大。低铈锆比储氧材料中的ZrO2对晶格缺陷具有很好的稳定作用,老化后低铈锆比材料的晶格缺陷多于高铈锆比材料,从而提高了低铈锆比材料中体相氧的移动性能。本文以La稳定氧化铝制备了低贵金属Pt+Rh/Al2O3催化剂和经系列储氧材料改性的系列Pt+Rh/Ce0.3+xZr0.6-xY0.1O1.95+Al2O3催化剂。结果表明,未经储氧材料改性的Pt+Rh/Al2O3催化剂性能较差,很难适应通用汽油机尾气净化要求;经储氧材料改性后的催化剂活性明显得到提高,且含低铈锆比储氧材料的催化剂活性及抗老化性能明显优于含高铈锆比储氧材料的催化剂,含低铈材料Ce0.35Zr0.55Y0.1O1.95的催化剂具有优异的温度特性、空燃比特性及抗老化性能,更多还原

【Abstract】 This paper studied the supports material of small gasoline engine exhausts purification catalysts and the small gasoline engine exhausts purification catalysts itself in detail. Based on the two kinds of prepared catalysts supports of series Ce0.3+xZr0.6-xY0.1O1.95 oxygen storage material and La stabilized Al2O3, the effects of Ce/Zr ratio on the property of surface area (BET), pore size, pore volume, oxyen storage capacity, cerium atom utilization, thermal stability, material structure and surface property of the series OSM Ce0.3+xZr0.6-xY0.1O1.95 was studied in detail. And the effects of Ce/Zr ratio on the property of temperature character, A/F character, catalysts structure and thermal stability of the series catalysts was also studied by different routine in detail. At last a kind of high performance low nobl metal small gasoline exhaust purification catalysts was prepared.A series oxygen storage material of Ce0.3+xZr0.6-xY0.1O1.95 and La-Al2O3 were prepared by co-precipitation routine and the property of these materials was studied by means of surface area (BET), oxygen storage capacity (OSC), temperature program reduction (H2-TPR), X-ray diffraction (XRD), transmission electronic microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The BET results indicated that the fresh La-Al2O3 possessed high surface area, lage pore volume and reasonable pore size distribution. After high temperature ageing, La-Al2O3 showed high thermal stability, and low Ce/Zr ratio material was more thermal stable than high Ce/Zr ratio material. The OSC and TPR results indicated that the Ce/Zr ratio had great effection on the property of oxygen storage capacity, cerium atom utilization ratio, reducibility and thermal stability. Low Ce/Zr ratio material更多还原