Atomic layer deposition of MoO3 on mesoporous γ-Al2O3 prepared by sol–gel method as efficient catalyst for oxidative desulfurization of refractory dibenzothiophene compound

Abstract

MoOx/Al2O3 based catalyst has long been widely used as an active catalyst in Oxidative Desulfurization reaction due to its high stability under severe reaction conditions and high resistance to sulfur poisoning. In this context, 4 and 9 Wt.% MoO3 grafted on mesoporous γ-Al2O3 has been synthesized using the modified atomic layer deposition (ALD) method. Another MoO3/Al2O3 sample was prepared by the conventional wetness impregnation (IM) method, for comparison. The effect of the preparation methods on the metal–support interaction was evaluated using different characterization techniques; including X-ray diffraction, X-ray photoelectron spectroscopy (XPS), N2-physisorption, transmission electron microscopy (TEM), H2-temperature-programmed reduction, and FT-IR. Oxidative desulfurization (ODS) reaction of the model fuel oil was used as a probe reaction to examine the catalytic efficiency of the prepared catalysts. ALD method led to samples with much better physicochemical properties than those of the prepared one via the impregnation method. However, the 9 Wt.% MoO3/Al2O3 (ALD) catalyst in the ODS reaction of model fuel oil shows remarkable catalytic performance with ~80%, which has been attributed to the more Mo6+ surface concentrations relative to Al3+ with large pore diameter and surface area. The kinetic study shows that the ODS of DBT follows a pseudo-first-order rate reaction.