Impacts of Ni-Loading Method on the Structure and the Catalytic Activity of NiO/SiO2-Al2O3 for Ethylene Oligomerization

To clarify the Ni species of NiO/SiO2-Al2O3 catalysts that are active for ethylene oligomerization, 18 types were prepared using three Ni-loading methods (i.e., ion-exchange, impregnation, and homogeneous precipitation), with different Ni-loadings (1–20 wt%), examined respect to their structure catalytic activity oligomerization. Characterized by N2 adsorption, powder XRD, FE-SEM, H2-TPR, NH3-TPD, C2H4-TPD showed in ion-exchange mainly ion-exchanged cations. In contrast, impregnation a mixture cations NiO particles, those precipitation all NiSiO3 particles. Catalytic-reaction tests at 300 °C 0.1 MPa revealed following: highest C2H4 conversion rate; particles moderate reaction not We concluded high was result dispersion medium-strength acidity, which together promoted adsorption activation on, desorption oligomerization products from, catalyst.