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用X光衍射相定量法测得La_2O_3和NiO在r-Al_2O_3,表面的最大单层载负量分别为0.28克/100米~2和0.09克/100米~2。用X光衍射峰半宽法测定了添加La_2O_3对还原态甲烷化催化剂中镍晶粒大小的影响。结果表明,通过硝酸盐浸渍热分解在甲烷化催化剂中加入La_2O_3,La_2O_3是以单层分散状态存在。镍附载在有单层La_2O_3改性的r-Al_2O_3表面,其晶粒要比没有La_2O_3时小得多。这就是甲烷化催化剂中添加希土元素氧化物后活性和热稳定性大大提高的一个主要原因。这个用单层分散的化合物使载体表面改性的概念,也可用于其它催化剂的研究中。
The maximum monolayer loading of La 2 O 3 and NiO on r-Al 2 O 3 was 0.28 g / 100m -2 and 0.09 g / 100m -2, respectively, as determined by X-ray diffraction. The effect of La 2 O 3 on the size of Ni grains in the reduced methanation catalyst was measured by X-ray diffraction peak half-width method. The results show that La_2O_3 is added to the methanation catalyst by thermal decomposition of nitrate impregnation, and La_2O_3 exists in a monolayer dispersion state. Nickel supported on a single layer of La_2O_3 modified r-Al_2O_3 surface, the grain is much smaller than the absence of La_2O_3. This is one of the main reasons why the activity and thermal stability of the methanation catalyst are greatly increased after the addition of the rare earth element oxide. The concept of surface modification of the support with monolayer dispersed compounds can also be used in the study of other catalysts.