Influence of Ligands on the Surface Characteristics of CoMo/γ‐Al2O3 and Hydrodesulfurization Catalytic Activity on Dibenzothiophene‐Type Compounds

Abstract Refractory sulfur compounds in fuel oils combust, releasing sulfur oxides (SOx) into the atmosphere, which is a significant source of pollution. In this study, we focused on comparing the surface properties and hydrodesulfurization (HDS) activity of CoMo‐(L)/γ‐Al 2 O 3 containing chelating ligands (L), specifically acetic acid (AA), with those of ethylenediaminetetraacetic acid (EDTA), citric acid (CA). CoMo/γ‐Al 2 O 3 , CoMo‐AA/γ‐Al 2 O 3 , CoMo‐EDTA/γ‐Al 2 O 3 and CoMo/γ‐Al 2 O 3 were prepared by hydrothermal treatment of the mixtures of Co(NO 3 ) 2 .6H 2 O and (NH 4 ) 6 Mo 7 O 24 .4H 2 O with stoichiometric Co/Mo ratios and enriched with chelating ligands (L=AA, CA and EDTA). Based on the product distributions of the hydrodesulfurization (HDS) of dibenzothiophene (DBT), a reaction pathway of dibenzothiophene (DBT) HDS was proposed to follow hydrogenation (HYD) and direct desulfurization (DDS) routes. In addition, the ligand modification of CoMo/γ‐Al 2 O 3 catalysts resulted in enhancement of surface properties and HDS activity which is in the order of CoMo‐CA/γ‐Al 2 O 3 (98 %)> CoMo‐AA/γ‐Al 2 O 3 (94 %) > CoMo‐EDTA/γ‐Al 2 O 3 (90 %) > CoMo/γ‐Al 2 O 3 (43 %). CoMo‐AA/γ‐Al 2 O 3 presented a higher HYD/DDS ratio compared to CoMo‐CA/γ‐Al 2 O 3 , CoMo‐EDTA/γ‐Al 2 O 3 , and CoMo/γ‐Al 2 O 3 , respectively which makes it a promising HDS catalyst.