Catalytic oxidative desulfurization technology of supported ceria based catalyst: Physicochemical and mechanistic studies

Abstract The catalytic oxidative desulfurization (Cat-ODS) process has emerged as a new technology to achieve ultra-low sulfur levels in diesel fuels. Various cerium based catalysts impregnated with Mn/Al 2 O 3 were developed in this study. The catalytic activity of Mn/Ce/Al 2 O 3 was higher than the monometallic catalysts, Ce/Al 2 O 3 . Under these optimum conditions: tert-butyl hydroperoxide (TBHP)/sulfur ratio of 3, 5.26%Mn/11.68%Ce/Al 2 O 3 , temperature of 45 °C, 30 min of reaction, complete removal of model organosulfur compounds were obtained. In addition, >90% of sulfur was removed in commercial diesel. High resolution transmission electron microscopy (HRTEM) analysis of 5.26%Mn/11.68%Ce/Al 2 O 3 showed the presence of Al 2 O 3 , CeO 2 and MnO 2 . The active sites responsible for the higher oxidative desulfurization activity were CeO 2 and MnO 2 . The mechanistic study showed that the reaction between TBHP and DBT was efficient to produce corresponding sulfone, instead of sulfoxide compound using 5.26%Mn/11.68%Ce/Al 2 O 3 catalyst.