In-situ formation of boehmite and ammonium aluminum carbonate hydroxide for facile synthesis of γ-Al2O3 as industrial catalyst support used for hydrodesulfurization

Abstract

Alumina-supported CoMo catalysts have been widely used for hydrodesulfurization of various kinds of feeds. In the current research, γ-Al₂O₃ was synthesized through the simultaneous formation of boehmite and ammonium aluminum carbonate hydroxide (AACH) precursors under controlled pH and temperature conditions. After optimization of the textural properties, γ-Al₂O₃ was utilized as catalyst support for the immobilization of catalytically active species and obtaining CoMo/γ-Al₂O₃-n (concentration of Al(NO₃)₃.9H₂O solutions (n) = 30, 40, 50, 60, 70, 80, 90, and 100 g/L) catalysts via wet impregnation technique. Moreover, this preparation method was applied for the successful large-scale synthesis of CoMo/γ-Al₂O₃-n. The catalyst was characterized by FT-IR, powder X-ray diffraction (XRD), thermogravimetric analysis, inductively-coupled plasma (ICP), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and Brunauer–Emmett–Teller (BET). The conversion of thiophene over CoMo/γ-Al₂O₃ was studied to assess the catalytic performance. The catalytic activity and stability of our reported catalyst were comparable with that of KATALCO_JM 41-6 T commercial catalyst.

Highlights

• Mixture of boehmite and AACH precursors was synthesized by co-precipitation method
• The precursors were thermally decomposed to extruded γ-Al₂O₃ as catalyst support
• The properties of γ-Al₂O₃ were tuned by various concentrations of Al solution
• CoMo/γ-Al₂O₃ was prepared by the impregnation of γ-Al₂O₃ in the Co and Mo solutions
• CoMo/γ-Al₂O₃ catalyst was sulfided and used for hydrodesulfurization of thiophene