An optimized highly active and thermo-stable oxidation catalyst Pd/Ce–Zr–Y/Al2O3 calcined at superhigh temperature and used for C3H8 total oxidation
An optimized highly active and thermo-stable oxidation catalyst Pd/Ce–Zr–Y/Al2O3 calcined at superhigh temperature and used for C3H8 total oxidation
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DOI：
10.1016/j.fuel.2012.08.051
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发表时间：
2013
期刊：
影响因子：
7.4
通讯作者：
Gang Wang;Rui You;M. Meng
中科院分区：
文献类型：
--
作者：
Gang Wang;Rui You;M. Meng
采用超声辅助浸渍法制备了一系列Y负载量（0%、2%、5%、10%）的Pd/Ce-Zr-Y/Al2O3催化剂，并将其用于C3H8全氧化反应。结果表明，这些催化剂在1100 ° C焙烧后仍具有较高的催化活性和热稳定性，特别是5%Y助剂的催化剂。此外，该催化剂还具有最佳的耐水蒸气性能。H2-TPR和XPS结果表明，在Pd/Ce-Zr/Al2O3中加入适量的Y，可以增强Pd物种与载体之间的相互作用，从而提高Pd物种的分散度。TEM、TPHD和CO脉冲化学吸附结果表明，含5%Y的Pd/Ce-Zr-Y/Al_2O_3催化剂具有最高的Pd分散度。然而，过量的Y会导致催化剂的BET比表面积显著降低，Pd物种的分散性降低，Pd物种与载体之间的相互作用减弱，从而导致催化剂的氧化活性降低。综合催化氧化性能、抗水汽性能和多项表征结果，认为含5%Y的Pd/Ce-Zr-Y/Al2O3催化剂在催化去除发动机冷启动过程中排放的碳氢化合物方面具有最大的应用潜力。
A series of supported catalysts Pd/Ce–Zr–Y/Al2O3with different Y loadings (0%, 2%, 5%, 10% by weight) were prepared by ultrasonic-assisted impregnation, and employed for C3H8total oxidation. It is found that these catalysts possess high catalytic activity and high thermal stability even after calcination at 1100°C, especially for the one promoted by 5% Y. In addition, this catalyst also exhibits best water-vapor resistance performance. The results of H2-TPR and XPS show that the addition of proper amount of Y to Pd/Ce–Zr/Al2O3can enhance the interaction between Pd species and the support, thus increasing the dispersion of Pd species. The TEM, TPHD and CO pulse chemisorption results conformably reveal that the catalyst Pd/Ce–Zr–Y/Al2O3containing 5% Y possesses the highest Pd dispersion as compared with others. However, excessive amounts of Y lead to remarkable decrease of BET surface area, lowering the dispersion of Pd species and weakening the interaction between Pd species and support; as a result, the catalyst exhibits lower oxidation activity. Combined with all the results of catalytic oxidation performance, water-vapor resistance performance and multiple characterizations, it is concluded that the Pd/Ce–Zr–Y/Al2O3catalyst containing 5% Y possesses the greatest application potential for the catalytic removal of hydrocarbon pollutants released by engines during cold-start period.