论文部分内容阅读
考察了焙烧温度对Pd/Al2 O3 和CeO2 改性Pd/Al2 O3 甲醇分解催化剂反应性能的影响。在 30 0℃～ 70 0℃范围内焙烧 ,Pd/Al2 O3 和Pd/CeO2 /Al2 O3 催化剂的活性都呈现出先升高后降低的趋势。XRD结果表明高温焙烧时活性组分Pd在γ Al2 O3 载体表面发生聚集是Pd/Al2 O3 催化剂活性降低的原因 ,而XPS结果却表明 ,Pd在CeO2 改性γ Al2 O3 载体表面的浓度与Pd/CeO2 /Al2 O3 催化剂的活性变化并非呈现一致关系 ,TPR表明活性组分Pd和助剂CeO2在γ Al2 O3 上产生了一定的相互作用。从而认为Pd的分散度以及Pd和CeO2 之间的相互作用共同决定催化剂的甲醇分解性能
The effects of calcination temperature on the catalytic performance of Pd / Al 2 O 3 and CeO 2 modified Pd / Al 2 O 3 catalysts for methanolysis were investigated. The activity of Pd / Al 2 O 3 and Pd / CeO 2 / Al 2 O 3 catalysts showed the trend of first increasing and then decreasing when calcined at 30 0-70 ℃. The results of XRD show that the activity of Pd on the surface of γ Al 2 O 3 carrier is decreased when the active component Pd is calcined at high temperature. However, the XPS results show that the concentration of Pd on the surface of CeO 2 modified γ Al 2 O 3 support and Pd / CeO2 / Al2 O3 catalyst activity change does not show a consistent relationship, TPR shows that the active component of Pd and CeO2 in γ Al2 O3 have a certain interaction. It is considered that the Pd dispersion and the interaction between Pd and CeO2 determine the methanol decomposition performance of the catalyst