Identifying the dominant effect of electron-feeding on molybdenum phosphonates to decipher the activity origin for oxidative desulfurization of fuel

Abstract

Electronic structure of active sites is crucial for oxidative desulfurization (ODS) process, while there is still a lack of direct experimental evidence to identify its real role on ODS activity. Herein, hollow spherical molybdenum phosphonate is designed through a facile hydrothermal method with the assistance of urea. The well-defined hollow spherical structure and homogeneous integration of organic moieties improve mass transfer during the heterogeneous ODS reaction. The combination of systemic characterizations, selective bromination and quenching experiment suggests that the introduction of –OH functional groups with strong electron-donating ability can modulate the electronic structure at molecular level, which provides continuous electron-feeding to Mo active sites, thus accelerating the ODS process. Correspondingly, the obtained catalyst delivers superior ODS performance with 100 % DBT conversion in 40 min at 60 ℃ and stable recyclability up to 10 times. This work can supply new inspiration for manipulating the nanostructures and electronic states of metal phosphonates for green catalysis.