Study on the performance and mechanism of aerobic oxidative desulfurization based on a dual-functional material possessing catalytic and adsorptive properties

Herein, three polyoxometalates, namely K3PW12O40·10H2O, K6[α-P2W18O62]·14H2O, and K8H[P2W15V3O62]·9H2O, were successfully prepared and used in the air/n-octanaloxidative desulfurization (ODS) system. Among the compounds, the Dawson-type polyoxometalate K6[α-P2W18O62]·14H2O exhibited the best performance, with a 99.63% desulfurization ratio. Then, K6[α-P2W18O62]·14H2O was supported on graphene oxide (GO) to obtain K6P2W18O62/GO. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), 31P nuclear magnetic resonance (31P NMR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), and Boehm titration. Using K6P2W18O62/GO as a catalyst, a final sulfur removal ratio of 96.10% was achieved without extraction post-treatment due to the inherent adsorption capacity of the catalyst. In addition, the factors influencing the desulfurization process were investigated. The recovery experiment showed that the supported catalyst could be reused 5 times with slight catalyst deactivation. Finally, the reaction mechanism was proposed with the aid of gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and contrast tests.