Immobilization of monodisperse metal-oxo-cluster on graphene for aerobic oxidative desulfurization of fuel

To meet the ever-upgrading sulfur-content standard of fuel oil, aerobic oxidative desulfurization (AODS) of fuel has become a research focus for its advantages of high efficiency and low cost. Herein, monodisperse polyoxometalate (POM) clusters immobilized by poly(ionic liquid) (PIL) have been successfully supported on graphene through a one-step bottom-up strategy and used as robust catalysts for AODS with air as oxygen source. Systematical characterizations were applied to investigate the structural features and formation mechanism. The catalyst synthesized via non-covalent interactions possessed high specific surface area and large mesoporous size. POM anionic clusters were uniformly monodispersed on the surface of the material, which endowed the catalyst with excellent heterogeneous catalytic performance. Detailed experiments for desulfurization of model fuel were subsequently performed to explore the influence of crucial parameters. The optimal catalyst achieved complete conversion of sulfides under mild condition, which could be reused at least six times without noticeable decreases of the catalytic performance. Based on the obtained results, the POM/PIL/Gr composite is expected to serve as efficient, robust and recyclable catalysts for ultra-deep oxidative desulfurization.