Comparison of Ni-S 2 O 8 2– /ZrO 2 –Al 2 O 3 Catalysts prepared by Microemulsion and Impregnation Methods and their Performance for Isomerisation

Abstract

Bifunctional Ni-S₂O₈^2–/ZrO₂–Al₂O₃ (Ni-SSZA) solid superacid catalysts were prepared by microemulsion (Ni-SSZA-M) and impregnation (Ni-SSZA-I) methods and their performance for n-pentane isomerisation was studied. The catalysts were characterised by BET, XPS, XRD, FTIR, Py–FTIR, TPR, TEM and CO uptake. The results show that, compared with the Ni-SSZA-I catalyst, the Ni-SSZA-M catalyst shows smaller and more uniform Ni particles, higher surface area, smaller crystallite size of tetragonal ZrO₂, more metal active sites and stronger acidity. The activity test indicated that loading Ni by the microemulsion method can significantly improve the isomerisation activity of the catalyst at lower reaction temperatures. In comparison with the Ni-SSZA-I catalyst, the isopentane yield for Ni-SSZA-M was improved by 11.6% and the optimum temperature was decreased by 60 °C.