Tungsten phosphide nanoparticles anchored on ultrathin carbon nanosheets for efficient oxidative desulfurization: Pivotal roles and generation pathways of singlet oxygen

Abstract

Singlet oxygen (¹O₂) is an excellent reactive oxygen species for the selective oxidation of organic compounds. Therefore, its application in oxidative desulfurization (ODS) of fuels is theoretically promising, while this has rarely been systematically investigated. Herein, a novel ultrathin carbon nanosheet (CN)-supported tungsten phosphide (WP) catalyst (WP/CN) was devised and employed to activate hydrogen peroxide (H₂O₂) for the efficient ¹O₂ generation in ODS. The turnover frequency of WP/CN for the oxidation of dibenzothiophene was as high as 32.7 h⁻¹ at 60 °C, surpassing that of most reported ODS catalysts. More importantly, benefiting from the high selectivity of ¹O₂, the WP/CN-H₂O₂ system exhibited exceptional interference resistance and achieved complete ODS of real diesels at a molar ratio of H₂O₂ to S of 4:1 (the theoretical value is 2:1), outperforming reported ODS systems. The results of experiments and density functional theory calculations demonstrated that the most reasonable reaction pathway for the formation of ¹O₂ was H₂O₂→H₂O₂*→2OH*→O*→2O*→¹O₂*. The present findings may provide new insights into the development of high-performance and energy-saving ODS processes.