甲烷部分氧化制合成气反应Pt/Al_2O_3和Pt/CeO2/Al_2O_3催化剂的研究(英文)

研究了Ｐｔ／Ａｌ２Ｏ３和Ｐｔ／ＣｅＯ２／Ａｌ２Ｏ３催化剂对甲烷部分氧化制合成气反应的催化活性，发现Ｐｔ／ＣｅＯ２／Ａｌ２Ｏ３显示了比Ｐｔ／Ａｌ２Ｏ３更高的甲烷转化率和合成气选择性。用Ｈ２ＴＰＲ，Ｈ２ＴＰＤ，ＳＥＭ和ＸＲＤ等手段和技术对催化剂进行了表征。ＣｅＯ２与Ｐｔ之间存在较强的相互作用（ＳＭＳＩ），这种作用促进了Ｐｔ在催化剂表面的分散，抑制了Ｐｔ在催化剂表面的迁移，大大降低了催化剂在反应中的完全燃烧活性，提高了催化剂的部分氧化活性和选择性，避免了因催化剂床层局部温度过高而导致催化剂活性下降或失活，提高了催化剂的稳定性。同时，在反应过程中，ＣｅＯ２通过促进水蒸气变换反应（ＷＧＳＲ）的进行使反应体系迅速达到平衡，提高了催化剂对Ｈ２的选择性。

REACTIVITY OF Pt/Al2O3 AND Pt/CeO2/Al2O3 CATALYSTS FOR PARTIAL OXIDATION OF METHANE TO SYNGAS

The reactivities of Pt/Al 2O 3 and Pt/CeO 2/Al 2O 3 for partial oxidation of methane to syngas have been studied. It was found that Pt/CeO 2/Al 2O 3 catalyst showed higher activity and selectivity than Pt/Al 2O 3. The catalysts were studied by temperature programmed reduction (TPR) and temperature programmed desorption as well as scanning electron microscopy (SEM) and X ray diffractometry (XRD). There is a strong interaction between ceria and platinum, which increases the dispersion of platinum on catalysts. As a result of this interaction, the activity of Pt/Al 2O 3 for methane total oxidation (combust reaction) was suppressed, and the activity and selectivity of catalyst for partial oxidation were improved significantly. Another role of ceria in catalyst is enhancing the WGSR during the reaction, which lead to an increase in the selectivity of catalyst for hydrogen.