Influence of water steam on the acitivity of melallic oxide catalysts in complete oxidation of p-xylene

  • Lưu Cẩm Lộc
  • Nguyễn Thị Diễm Phúc
  • Hồ Sĩ Thoảng

Abstract

Physico-chemical characteristics and activity of mono- and poly-oxide catalyst, based on CuO, Cr203, MnO2, CeO2 on γ- and α-Al203 as carriers. have been studied. Interactions between active phases as well as interactions of active phases with carriers and promoting additive CeO2 were characterized by BET, XRD and TPR methods. Activity of the catalysts was determined in complete oxidation of p-xylene at the temperature range 200 - 340oC in a flow of nitrogen, containing molecular oxygen and various concentrations of water steam. It has been found that all poly-oxide catalysts (CuO-Cr203, CuO-Mn2, CuO-MnO2-Cr2O3 supported on γ - as well as α - Al203) expressed the highest activity; the catalysts containing single oxide indicated less activity, but an addition of CeO2 improved their activity except for the catalyst of 15%MnO2/γ- Al203 modified by 7% CeO2. In the presence of water steam, except for CuO, all mono-oxide catalysts indicated the less stability. Cr2O3 has been found to be a stabilizing component in poly-oxide catalysts. The catalyst 5%MnO2+2%CeO2/α- Al203 has been indicated as the most stable one in the presence of water steam. The activity as well as the stability of catalysts were discussed in the relation with their physico-chemical properties.

điểm /   đánh giá
Published
2012-02-07
Section
Articles