Acta Chimica Sinica ›› 2004, Vol. 62 ›› Issue (20): 1981-1987. Previous Articles     Next Articles


毕玉水, 吕功煊   

  1. 中国科学院兰州化学物理研究所, 羰基合成与选择氧化国家重点实验室, 兰州, 730000
  • 收稿日期:2004-03-22 修回日期:2004-06-17 出版日期:2004-10-28 发布日期:2014-02-17
  • 通讯作者: 吕功煊,;Tel:0931-4968178;Fax:0931-4968178.
  • 基金资助:

Influences of Transition Metal Additives on CO Oxidation over NaZSM-5 Supported Pd

BI Yu-Shui, LÜ Gong-Xuan   

  1. State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000
  • Received:2004-03-22 Revised:2004-06-17 Online:2004-10-28 Published:2014-02-17

A series of transition metal-modified Pd-M-Ox-NaZSM-5 (M=Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Zr) catalysts were prepared by co-impregnation and sequential impregnation methods separately. Influences of different preparation methods on CO oxidation have been studied. It was found that catalysts prepared by co-impregnation method were superior to those of the sequential one. Effects of temperature, content of the promoter, H2 pre-reduction, space velocity and moisture in the feed gas on Pd-Fe-Ox/NaZSM-5 catalyst prepared by co-impregnation method for CO oxidation have been investigated in detail. XRD and XPS techniques were used to verify the species in the catalyst. The addition of Fe2O3 obviously improved the activity and CO conversion increased with the increase of reaction temperature or Fe-loading amount. However, high space velocity as well as H2 pre-reduction decreased the activity. The catalyst was sensitive to moisture and its activity was easily depressed by moisture in the feed gas. XRD showed that Pd species were highly dispersed on the surface of NaZSM-5, which was dependent upon the Fe-loading amount of hematite. XPS profiles revealed the presence of synergism between Fe2O3 and Pd species, and the Pd species kept a high oxidation state in the special structure of NaZSM-5. High dispersion of the Pd species as well as the synergism between Fe and the Pd species was responsible for the enhancement of catalytic activity.

Key words: transition metal, Pd2Fe2Ox/NaZSM-5, supported catalyst, low temperature, CO oxidation