【作者】 任屹罡；

【导师】 龚茂初；

【作者基本信息】 四川大学 ， 物理化学， 2004， 硕士

【摘要】 本文以堇青石为第一载体,储氧材料(OSM)及改性Al2O3为第二载体,以Co为活性组分,Mn为助剂,制备了一系列整体式甲烷燃烧催化剂。利用连续流动微型反应装置研究了催化剂的稀薄甲烷催化燃烧反应性能,抗高温老化性能,并用XRD,BET,H2-TPR等手段对催化剂进行了表征。 XRD测试结果表明,Co在各个催化剂样品的表面都具有良好的分散性。活性测试结果表明,对于以Co为活性组分的催化剂体系,在镱和锆改性氧化铝(YSZ-Al2O3),OSM,YSZ-Al2O3+OSM三种载体中,YSZ-Al2O3+OSM作为载体有着最佳性能。Co在YSZ-Al2O3和YSZ-Al2O3+OSM这两种载体上的最佳负载量都是为10%(重量百分比,以金属单质重量计)。比较了两种载体混合后再浸渍Co制备的Co/YSZ-Al2O3+OSM催化剂,以及两种载体分别浸渍Co以后再混合制备的Co/YSZ-Al2O3+Co/OSM催化剂的活性,结果表明后者的甲烷催化燃烧活性明显高于前者。 对于分浸法制备的Co/YSZ-Al2O3+Co/OSM催化剂体系,当Co/OSM含量为50%时,催化剂活性最佳,可在550℃将1%的稀薄甲烷完全转化。同时,H2-TPR测试结果表明,催化剂中的Co/OSM比例越高,催化剂的还原性能越好。但对于1000℃老化以后的催化剂,活性顺序则发生了改变, Co/OSM含量为75%时性能最好。 实验结果还表明,对于Co/OSM催化剂体系,三组分(Ce-Zr-Mn)储氧材料中的Mn含量对OSM本身性能影响相对较小,但是对于催化剂活性有着显著影响。而当Mn作为助剂添加到催化剂中,较少的添加量即可以改善含锰催化剂Co/OSM的性能,对于不含锰的Co/YSZ-Al2O3催化剂则需要相对较大的添加量才能改善催化剂性能。 3<WP=5>四川大学硕士学位论文实验结果也表明,稀薄甲烷在催化剂上的燃烧情况比常规浓甲烷的燃烧情况更加接近于实际情况。更多还原

【Abstract】 A series of cobalt-based catalysts with different supports have been preparedusing impregnation method, and characterized by BET,XRD and H2-TPR。Thecatalytic activities for methane combustion were assessed in a micro-reactor。 The results show that OSM is kind of good support for methane catalyticcombustion catalysts。YSZ-Al2O3+OSM supported cobalt monolith catalysts wasfound to have the highest activity amongst Ce0.25Zr0.50Mn0.25O2 (oxygen storagematerials),YSZ-Al2O3 (Y2O3 and ZrO2 stabilized alumina),YSZ-Al2O3 +OSMsupported catalysts。 The methane combustion activity of the YSZ-Al2O3+OSMsupported cobalt catalyst is first increased, passes through a maximum and thendecreases with increasing the content of cobalt from 1wt% to 20wt%, the maximumactivity was observed for the catalyst with 10wt% of cobalt。The methanecombustion activity of the Co/YSZ-Al2O3+Co/OSM is first increased, passesthrough a maximum and then decreases with increasing the content of Co/OSM , themaximum activity was observed for the catalyst with 50wt% of Co/OSM。However, aged at high temperature, maximum activity of the Co/YSZ-Al2O3 after the+Co/OSM was observed for the catalyst with 75wt% of Co/OSM。The content ofMn in OSM was found to have a profound influence on activity of Co/OSMcatalyst。 XRD revealed cobalt were high disperse on YSZ-Al2O3,a further promotion ofdisperse is observed with the introduction of Co/OSM into Co/YSZ-Al2O3。H2-TPR 5<WP=7>四川大学硕士学位论文revealed that higher the content of OSM in support,higher the reductive of catalysts。The reductive of the Co/YSZ-Al2O3 +Co/OSM increase with increasing thecontent of Co/OSM。 The combustion conditon of dilute methane is more close to the factthan dense methane’s。更多还原