Hydrodesulfurization of dibenzothiophene and 4,6-dimethyl-dibenzothiophene:Gallium effect over NiMo/Al_2O_3 sulfided catalysts

摘要

The influence of gallium on alumina-supported NiMo catalysts was investigated by correlating their physicochemical properties with the hydrodesulfurization (HDS) activity of model molecules.The Ga-gamma-Al_2O_3 supports were prepared by impregnation of Ga (0.6-5.9 wt%) on gamma-A1_2O_3.The NiMo catalysts were prepared following the same method on calcined Ga-Al_2O_3.The N_2-physisorption results showed that Ga did not affect the textural properties of both gamma-Al_2O_3 and NiMo/gamma-Al_2O_3.When the Ga-Al_2O_3 supports were calcined at 723 K all Ga ions presented a high dispersion,forming a different structure than that observed in bulk Ga_2O_3.The XPS and the TPR-S showed that the Ga addition modified the structural properties of NiMo depending on the amount of Ga.In the HDS of DBT and 4,6-DMDBT,the Ga-Al_2O_3 supported NiMo catalysts at loadings of Ga below to 1.2 wt% showed higher activity than that of a NiMo/Al_2O_3 sample.