Catalytic properties of NiSO4/ZrO2 promoted with Fe2O3 for acid catalysis

Abstract

A series of catalysts, NiSO4/Fe2O3–ZrO2, for acid catalysis were prepared by the impregnation method, where support, Fe2O3–ZrO2 was prepared by the co-precipitation method using a mixed aqueous solution of zirconium oxychloride and iron nitrate solution followed by adding an aqueous ammonia solution. No diffraction line of nickel sulfate was observed up to 20wt.%, indicating good dispersion of nickel sulfate on the surface of Fe2O3–ZrO2. The addition of nickel sulfate (or Fe2O3) to ZrO2 shifted the phase transition of ZrO2 from amorphous to tetragonal to higher temperature because of the interaction between nickel sulfate (or Fe2O3) and ZrO2. 15-NiSO4/Fe2O3–ZrO2 containing 15wt.% NiSO4 and 5mol% Fe2O3, and calcined at 700°C exhibited maximum catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation. The catalytic activities for both reactions were correlated with the acidity of catalysts measured by the ammonia chemisorption method. The addition of Fe2O3 up to 5mol% enhanced the acidity, thermal property, and catalytic activities of NiSO4/Fe2O3–ZrO2 gradually due to the interaction between Fe2O3 and ZrO2 and consequent formation of FeOZr bond.