NiW/MgO–TiO2 catalysts for dibenzothiophene hydrodesulfurization: Effect of preparation method

Abstract In the present work NiW-based catalysts supported on binary MgO–TiO 2 mixed oxides (MT- x , were x is the mol% of TiO 2 ) were prepared by aqueous and non-aqueous methods. The results from the characterization techniques (N 2 adsorption/desorption, XRD, UV–vis DRS and HRTEM) were used to establish a relationship between the preparation method and the structural changes of W phases as well the catalytic activity. N 2 adsorption/desorption isotherms showed higher surface areas with the increase on mol% of TiO 2 . Catalysts characterization showed that the preparation method did not change the original structure of the supports. Furthermore, the presence of NiO and NiWO 4 was not observed in any sample, thus, the supports allowed a good dispersion of Ni and W species. DRS spectra showed the presence of W 6+ in octahedral coordination and tetrahedral Ni 2+ . Correlation of the catalytic activity in the DBT HDS reaction and the fraction of W atoms on the edge of WS 2 crystallites indicated that the aqueous impregnation on MT25, followed by drying at 393 K leads to the formation of a greater number of catalytically active sites available for interaction with DBT molecules.