Synthesis of Mo-Ta bimetallic oxide catalyst with crystal phase regulation strategy for efficient catalytic oxidation of 4,6-DMDBT in diesel

Abstract

Oxidative desulfurization (ODS) technology mainly involves selectively oxidizing sulfides in diesel fuel into sulfone utilizing highly efficient catalysts to prepare clean fuel, especially using molecular oxygen as an oxidant. Bimetallic oxide is a feasible catalyst for the ODS process owing to its superior catalytic activity. Herein, a series of molybdenum-tantalum bimetallic oxide catalysts (MoTaOx) with different crystalline phases were successfully fabricated by co-precipitation combined with calcinating at different temperatures. The characterization experimental results manifested that the calcination temperature observably affected the formation of crystalline phase of MoTaOx as well as the catalytic activity. Meanwhile, the activity tests demonstrated that the MoTaOx-750 catalyst exhibited outstanding sulfur removal efficiency on 4,6-DMDBT in ODS system, achieving ultra-deep desulfurization (100 %) within 9 h at 120 °C. The excellent oxidative desulfurization activity was attributed to the synergistic effect of Mo-Ta bimetal exposing more active centers. Finally, a possible reaction mechanism was proposed and the obtained catalyst showed a long-life utilization without deteriorating rather noticeably in catalytic activity after 26 cycles.