Effect of Polyethylene Glycol Addition on Hydrodesulfurization Activity over CoO-MoO<sub>3</sub>/Al<sub>2</sub>O<sub>3</sub> Catalyst

Abstract

A new additive approach using polyethylene glycol (PEG) as a water soluble organic compound was proposed to improve hydrodesulfurization activity over CoO-MoO3/Al2O3 catalyst. The addition of PEG to the impregnation solution during the course of catalyst preparation significantly improved thiophene, dibenzothiophene and light gas oil hydrodesulfurization activity. XPS and TEM measurements indicated that the positive effect of PEG can be attributed to suppression of cobalt and molybdenum aggregation and increasing the number of active sites. Without PEG addition, the cobalt and molybdenum precursors tended to aggregate during the drying step due to weak interaction with the alumina support. Addition of PEG to the impregnation solution maintained high dispersion of cobalt and molybdenum precursors on the alumina support even after water removal, since PEG has higher boiling point than water. Consequently, higher dispersion of cobalt and molybdenum was maintained, because they remained dissolved in the PEG.