A Comparative Study of Ni-Based Catalysts Prepared by Various Sol-Gel Routes.

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Heterogeneous catalysts are crucial for advancing green chemistry and reducing industrial costs.
• Mesoporous silica-alumina mixed oxides offer tunable properties for catalytic applications.

Purpose of the Study:

• To synthesize and characterize mesoporous silica-alumina supports with varying Si/Al ratios using hydrolytic sol-gel (HSG) and non-hydrolytic sol-gel (NHSG) methods.
• To evaluate the performance of derived silica-alumina-nickel oxide catalysts in ethylene oligomerization.

Main Methods:

• Sol-gel synthesis (HSG and NHSG) with different oxygen donors (ethanol, diisopropyl ether).
• Characterization techniques including EDX, N2 physisorption, XRD, MAS-NMR (29Si, 27Al), and NH3-TPD.
• Ethylene oligomerization reaction at 150 °C.

Main Results:

• NHSG routes produced more regularly distributed and acidic mesoporous silica-alumina supports compared to HSG.
• Silica-alumina-nickel oxide catalysts prepared via the NHSG ether route exhibited superior activity in ethylene oligomerization.
• Catalyst performance was correlated with support acidity and structural regularity.

Conclusions:

• The non-hydrolytic sol-gel (NHSG) method, particularly the ether route, is effective for preparing highly active mesoporous silica-alumina-nickel oxide catalysts.
• Enhanced catalyst acidity and structural regularity achieved through NHSG contribute to improved ethylene oligomerization.
• This research supports the development of efficient heterogeneous catalysts for green chemistry applications.