Investigation on the Catalytic Cracking Mechanism of CuO on Dimethyl Sulfoxide (C2H6OS) and Surface Modification Effects: Insights from Density Functional Theory Calculations

Abstract

To explore the catalytic cracking mechanism of CuO on oil shale and the catalytic activity of surface modifications of CuO on oil shale, dimethyl sulfoxide (C2H6OS) is used as a model molecule representative of organic sulfur compounds in oil shale, and the adsorption and dissociation behaviors of C2H6OS molecules on pure and OH pre-adsorbed CuO(111) surfaces were investigated by density functional theory calculations. The results indicate that C2H6OS selectively adsorbs at the Cusub sites via the S atom and decomposes through cleavage of the C–H bond prior to the breaking of the C-S bond on both surfaces. The presence of OH on the CuO(111) surface promoted the dissociation of C2H6OS. The energy barriers of dehydrogenation and desulfurization of C2H6OS on the OH pre-adsorbed CuO(111) surface were 20.0 and 19.3 kcal/mol, respectively, which are 41% and 49% lower than those on pure surfaces. The present results provide crucial guidance for the synthesis and improvement of high-performance pyrolysis catalysts specifically designed for oil shale applications. Additionally, they also present important data regarding to the thermal stability of C2H6OS in the presence of incompatible substances.