Industrial & Engineering Chemistry Research, Vol.53, No.37, 14253-14262, 2014
Influence of Zirconium Addition in Platinum-Hexagonal Mesoporous Silica (Pt-HMS) Catalysts for Reforming of n-Heptane
A series of platinum/zirconium-hexagonal mesoporous silica (Pt/Zr-HMS) catalysts with different molar ratios of Si/Zr have been prepared and used for reforming reaction. The prepared catalysts were characterized by XRD, XRF, NH3-TPD, FTIR, Py-IR, nitrogen sorption, SEM, and TGA (for studying the coke deposition) techniques. The effects of various amounts of zirconium on the activity, selectivity, and coke deposition in the temperature range of 200-500 degrees C were compared. By increasing the incorporation of Zr into the Pt-HMS structure, the acidity of catalysts increased. The results show that the catalytic activity and selectivity for desired products (especially isomerization products) increased with decreasing Si/Zr amount (or increasing zirconium content). The best i-C-7 selectivity (64.1%) was observed for Zr(5)-HMS at T = 200 degrees C.