Synergistic catalysis of the N-hydroxyphthalimide on flower-like bimetallic metal-organic frameworks for boosting oxidative desulfurization

Synergic catalytic effect between active sites and supports greatly determines the catalytic activity for the aerobic oxidative desulfurization of fuel oils. In this work, Ni-doped Co-based bimetallic metal-organic framework (CoNi-MOF) is fabricated to disperse N-hydroxyphthalimide (NHPI), in which the whole catalyst provides plentiful synergic catalytic effect to improve the performance of oxidative desulfurization (ODS). As a bimetallic MOF, the second metal Ni doping results in the flower-like morphology and the modification of electronic properties which ensure the exposure of NHPI and strengthen the synergistic effect of the overall catalyst. Compared with the monometallic Co-MOF and naked NHPI, the NHPI@CoNi-MOF triggers the efficient activation of molecular oxygen and improves the ODS performance without an initiator. The sulfur removal of dibenzothiophene-based model oil reaches 96.4% over the NHPI@CoNi-MOF catalyst in 8 h of reaction. Furthermore, the catalytic product of this aerobic ODS reaction is sulfone, which is adsorbed on the catalyst surface due to the difference in polarity. This work provides new insight and strategy for the design of a strong synergic catalytic effect between NHPI and bimetallic supports toward high-activity aerobic ODS materials.