Transition Metal Containing Mesoporous Silica as Effective Catalysts Support For Hydrodeoxygenation of Dibenzofuran to Transportation Fuels Molecules.
In continuation of our previously published researches in Fuel Journal, we move ahead to explored the potential of metal doped mesoporous silica for hydrodeoxygenation of dibenzofuran to fuel graded molecules. To actualized that, titanium containing Ti-MCM-41 and MCM-41 as catalysts supports, were synthesized via hydrothermal method and their physicochemical properties were examined through XRD, FTIR, UV-VIS, NH3-TPD, and N2 isothermal adsorption analysis. These support were co-impregnated with Ni(NO3)2.6H2O and Cu(NO3)2.3H2O solutions, dried, calcined and reduced with H2. Prior to calcination, the dried samples were analysed by TPO and after calcinations by TPR then further characterized by XRD, Raman, BET, FESEM and XPS and. The XRD and BET analysis of supports disclose the formation of hexagonal structures with larger surface area and medium pore size distribution in both MCM-41 and Ti-MCM-41 support. The FTIR and UV-Visible spectroscopic analysis described the existence of tetrahedrally co-ordinated titanium species in the silica matrix which generated strong Lewis sites as indicated by NH3-TPD. On the other hand, The Raman and XRD of supported catalysts revealed the existence of cubic phase of NiO. H2-TPR and XPS results show that, Cu2+ and Ni2+ were simultaneously reduced to Cu0 and Ni0, to formed bimetallic Cu-Ni alloy. A high dispersion of Cu-Ni particles were obtained, as evidenced by FESEM studies. The supported catalysts were tested for hydrodeoxygenations of Dibenzofuran at reaction temperature of 260oC, hydrogen pressure of 10MPa and 6hrs reaction time. The NiCu/Ti-MCM-41 proved to be highly active with 97.22% DBF conversion than NiCu/MCM-41 with 46.63% DBF conversion. Similarly, its indicates higher selectivity to bicyclohexane of 67.50% than NiCu/MCM-41 with 11.82%. The Products distribution showed that, hydrogenolysis pathway predominate over Ti-MCM-41 supported catalysts via C(SP2)-O cleavage while hydrogenation pathway predominates over MCM-41 supported catalysts via aromaticity lost. According to effect of time, both conversion and selectivity increase with increase of reaction time.
Key word- Ti-MCM-41, Hydrodeoxygenation, Dibenzofuran, Reaction time, transition metals