Characterization of nickel sulfate supported on SiO2 for ethylene dimerization and promoting effect of Al2O3 on catalytic activity

A series of catalysts, NiSO4/SiO2, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. No diffraction line of nickel sulfate was observed up to 20 wt%, indicating good dispersion of nickel sulfate on the surface of SiO2 and SiO2–Al2O3. The addition of Al2O3 to NiSO4/SiO2 improved the thermal stability of catalyst and increased the number of acid sites on the surface of catalyst. Consequently, the Al2O3-promoted catalyst exhibited remarkably higher catalytic activity than non-promoted NiSO4/SiO2. The catalytic activities of supported NiSO4 catalysts were correlated with the acidity of catalysts measured by the ammonia chemisorption method, regardless of the kind of support (SiO2 or SiO2–Al2O3).

Graphical abstractA series of catalysts, NiSO4/SiO2, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. The addition of Al2O3 to NiSO4/SiO2 improved the thermal stability of catalyst and increased the number of acid sites on the surface of catalyst. Consequently, Al2O3-promoted catalyst exhibited remarkably higher catalytic activity than non-promoted NiSO4/SiO2. The catalytic activities of supported NiSO4 catalysts were correlated with the acidity of catalysts measured by the ammonia chemisorption method. Figure optionsDownload full-size imageDownload as PowerPoint slide