Synthesis of Mesoporous γ-Al2O3 with Spongy Structure: In-Situ Conversion of Metal-Organic Frameworks and Improved Performance as Catalyst Support in Hydrodesulfurization

Abstract

Over the past decades, extensive efforts have been devoted to modulating the textural properties, morphology and microstructure of γ-Al2O3, since the physiochemical properties of γ-Al2O3 have close correlations with the performance of hydrotreating catalysts. In this work, a spongy mesoporous γ-alumina (γ-Al2O3) was synthesized using Al-based metal-organic frameworks (Al-MOFs) as precursor by two-step pyrolysis, and this Al-MOF-derived γ-Al2O3 was used as hydrodesulfurization (HDS) catalyst support, to explore the effect of support on the HDS performance. Compared with industrial γ-Al2O3, the spongy alumina displayed well-developed porosity with relatively high surface area, large pore volume, and abundant weak Lewis acid sites. Based on catalyst characterization and performance evaluation, sulfurized molybdenum and cobalt molecules were able to incorporate and highly disperse into channels of the spongy mesoporous alumina, increasing the dispersion of active catalytic species. The spongy γ-Al2O3 was also able to enhance the diffusion efficiency and mass transfer of reactant molecules due to its improved texture properties. Therefore, the corresponding catalyst presented higher activities toward HDS of dibenzothiophene (DBT) than that from industrial alumina. The spongy mesoporous γ-alumina synthesized by Al-MOFs provides a new alternative to further develop novel γ-alumina materials with different texture and various nanoporous structures, considering the diversity of MOFs with different compositions, topological structures, and morphology.

Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol

“…Table 1 shows that the specifi c surface areas (S BET ) derived from the adsorption isotherms increase in the following order: TiO 2 < ZrO 2 < C < Al 2 O 3 < SiO 2 , within the range of 8-212 m 2 /g. This correlation corroborates with the previously reported textural properties of oxide and carbon supports [27,28].…”

Aluminium-Based Metal–Organic Framework Nano Cuboids and Nanoflakes with Embedded Gold Nanoparticles for Carbon Dioxide Fixation with Epoxides into Cyclic Esters

“…We employed 4-amino triazole and 5-amino tetrazole in the materials synthesis as mediators of crystallisation, and two types of Al-MOFs have been obtained differing slightly in morphology labelled as Al4@NDC, Al5@NDC, respectively. So far, Al-based MOFs with NDC as a linker have been obtained using the solvothermal method in water solutions [35][36][37].…”

Clean Syn-Fuels via Hydrogenation Processes: Acidity–Activity Relationship in O-Xylene Hydrotreating

“…Due to increased environmental concern, the European Union has introduced the "zero-sulphur" legislation, which limits the sulphur content in gasoline and diesel less than 10 mg/kg [1], thus requiring the development of modern process technologies and the improvement of the actual hydrotreating catalysts for "very real" clean-fuels manufacturing [2,3]. Transition metal sulfide catalysts, usually consisting in molybdenum (Mo) supported on high surface area carriers and promoted by cobalt (Co) or nickel (Ni), are widely used in crude oils hydrotreatment [4][5][6][7][8][9]. The catalytic synergism of these systems relies on the formation of Co(or Ni)MoS phases, where the active sites are placed on both the metal and sulfur edges, and BRIM sites [10][11][12].…”