MoS2 nanocrystals embedded in hierarchical hollow carbon microspheres for efficient aerobic oxidative desulfurization

Abstract

Aerobic oxidative desulfurization (AODS) is an emerging sustainable technology for deep desulfurization of petroleum fuels, which requires robust catalysts to boost the efficient aerobic oxidation of thiophenes. Here we report a self-assembly approach to anchor homogeneously dispersed MoS2 nanocrystals into hierarchical hollow carbon microspheres for the efficient AODS of thiophenic sulfides. We show that MoS2 nanocrystals are vertically embedded in carbon nanosheets with highly active edge sites exposed to the surface, which could activate the aerobic oxidation of dibenzothiophene at 100 °C, and achieves a turnover frequency of 7.53 h–1, higher than that of the reported metallic oxide catalysts. Through a combination of experimental research and theoretical calculations, we demonstrate that the Mo edge of MoS2 can effectively activate oxygen and strongly adsorb sulfides, which endows our catalyst with extraordinary performance. Moreover, the close coupling of MoS2 nanocrystals in carbon ensures their chemical stability, so that the catalyst maintains unattenuated activity and unchanged chemical structure over seven repeated uses. This work provides both fundamental and practical insights in the design of efficient and stable nanocrystal-based catalysts.