Catalytic oxidative desulfurisation over Co/Fe-γAl₂O₃ catalyst: performance, characterisation and computational study

The world faces the challenge to produce ultra-low sulfur diesel with low-cost technology. Therefore, this research emphasised on production of low sulfur fuel utilising nanoparticle catalyst under mild condition. A small amount of cobalt oxide (10-30 wt%) was introduced into the Fe/Al₂O₃ catalyst through the wet impregnation method. Cobalt modification induces a positive effect on the performance of the iron catalyst. Hence, the insertion of cobalt species into Fe/Al₂O₃ led to the formation of lattice fringes in all directions which resulted in the formation of Co₃O₄ and Fe₃O₄ species. The optimised catalyst, Co/Fe-Al₂O₃, calcined at 400 °C with a dopant ratio of 10:90 indicating the highest desulfurisation activity by removing 96% of thiophene, 100% of dibenzothiophene (DBT) and 92% of 4,6-dimethyl dibenzothiophene (4,6-DMDBT). Based on the density functional theory (DFT) on Co/Fe-Al₂O₃, two pathways with the overall energy of -40.78 eV were suggested for the complete oxidation of DBT.