Aerobic Oxidative Desulfurization by Nanoporous Tungsten Oxide with Oxygen Defects

Abstract

Alkyl-substituted dibenzothiophenes such as 4,6-dimethyldibenzothiophene are a kind of typical refractory sulfur compound in fuel oil. Herein, three-dimensional ordered macro–mesoporous (3DOM) tungsten oxide catalysts were successfully prepared for aerobic oxidative desulfurization of 4,6-dimethyldibenzothiophene. The experimental results indicated that the as-prepared material 3DOM WO x -400 not only contained a hexagonal packed nanoporous structure but also abundant oxygen defects on its skeleton, exhibiting aerobic oxidative desulfurization of over 99% in 4 h. Moreover, sulfur removal could still reach 99% after recycling five times. Through free radical capture experiments, the superoxide radical is reasonably proposed in the mechanism. This work would provide a feasible route to develop highly efficient nanoporous materials for desulfurization of fuels.

New Type of Catalyst for Efficient Aerobic Oxidative Desulfurization Based On Tungsten Carbide Synthesized by the Microwave Method

“…It is known from the literature that the addition of radical traps to the system makes it possible to determine how oxygen is activated. 69 In particular, it was shown 33 that active centers consisting of tungsten in an intermediate oxidation state can activate oxygen by forming a superoxide radical. The formation of this radical was confirmed by the addition of benzoquinone, which is a well-known superoxide radical trap, to the system.…”

“…The results obtained on the presence of tungsten in a transitional oxidation state, as well as on the activation of oxygen through the superoxide radical, are in a good agreement with the literature data. 33 …”

“…Nanoporous tungsten oxide containing pentavalent tungsten in addition to the hexavalent one has been successfully used recently as a catalyst for aerobic oxidation. 33 The presence of defects in the catalyst structure, as well as tungsten in an intermediate oxidation state, made this catalyst highly efficient for the oxidation of DBT and dimethyldibenzothiophene under mild conditions (temperature, 120 °C). It was shown for the first time in this work that tungsten in an intermediate oxidation state enables the activation of air oxygen with the formation of a superoxide radical.…”

A current overview of the oxidative desulfurization of fuels utilizing heat and solar light: from materials design to catalysis for clean energy

“…Recently, Zhang et al impregnated W precursors in the structure of poly(methyl methacrylate) and performed calcination to eliminate the template and oxidize the W to engineer 3D nanoporous WO 3 with oxygen defects (3DOM WO x ). 74 The 3DOM WO x fabricated at different calcination temperatures demonstrated different rates of 4,6-DMDBT oxidation owing to morphology variations. As seen in the SEM images (Fig.…”

Engineering the Electronic Structure of Mo Sites in Mn–Mo–O Mixed-Metal Oxides for Efficient Aerobic Oxidative Desulfurization

“…24 Besides, the steric effect of methyl groups may also impact the reaction, resulting in the conversion efficiency of 4,6-DMDBT to be slightly lower than that of DBT. 63,64 Furthermore, the reaction products were identified using gas chromatography-mass spectrometry (GC-MS), which were verified to be sulfones (Figure S6). The circulation and stability of catalysts directly affect the economic benefits in actual applications.…”