The oxidative desulfurization process performed upon a model fuel utilizing modified molybdenum based nanocatalysts: Experimental and density functional theory investigations under optimally prepared and operated conditions

Abstract

CoMo/reduced graphene oxide (rGO) catalyst was synthesized for the oxidative desulfurization process (ODS) of dibenzothiophene (DBT) in n-decane. Parameters including total metal (Co and Mo) loading, Co/Mo and CA (citric Acid)/Mo molar ratios were investigated toward achieving optimum conditions. The catalysts were characterized by the XRD, ICP, FTIR, Raman Spectroscopy, BET-BJH, NH3-TPD, XPS, and TEM methods. The product sulfur content was measured by the ICP-OES while the product was evaluated using FTIR and 1H NMR analyses. All experimental stages were designed using Design-Expert software. High BET area, acidity, uniform particle size, and Co-promoter played key roles in this performance. Results revealed 99% for the DBT conversion in 1 h using CoMo (20)/rGO catalyst. The density functional theory (DFT) showed enhancement of interaction energy of the DBT by about 1215 kJ/mol. This emphasized the observed faster ODS reaction. Besides, it was demonstrated that the charge was transferred mainly from rGO to CoMo amplifying both production of interfacial built-in electric field and electrostatic interaction of DBT with the catalyst surface.