Amorphous Cr₂WO₆-Modified WO₃ Nanowires with a Large Specific Surface Area and Rich Lewis Acid Sites: A Highly Efficient Catalyst for Oxidative Desulfurization

Abstract

The oxidative desulfurization (ODS) of fuel oils is of great significance for environmental protection, and the development of efficient ODS heterogeneous catalysts is highly desired. Herein, we have designed and synthesized a novel material of amorphous Cr2WO6-modified WO3 (a-Cr2WO6/WO3) nanowires (3–6 nm) with a large specific surface area of 289.5 m2·g–1 and rich Lewis acid sites. The formation of such a unique nanowire is attributed to the adsorption of Cr3+ cations on non-(001) planes of WO3. In the ODS process, the a-Cr2WO6/WO3 nanowires can efficiently oxidize benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to their corresponding sulfones in a quasi-microemulsion reaction system and possess the highest activity (E a = 55.4 kJ/mol) for DBT: 99.0% of 15,000 ppm DBT with 2600 ppm S can be removed (70 °C, H2O2 as the oxidant). The improvement in ODS activity from most of WO3 catalysts is owing to the sufficient active sites and enhanced adsorption of DBT on the basis of structural features of a-Cr2WO6/WO3 nanowires. Combined with free radical capture experiments, a possible ODS mechanism of W­(O2) peroxotungstate route based on surface −OH groups is reasonably proposed. Moreover, the a-Cr2WO6/WO3 nanowires have good stability and can be synthesized on a large scale, suggesting its potential applications as an efficient heterogeneous catalyst.

Synthesis, characterization and catalytic performance of magnetic La0.7Sr0.3MnO3/α-Fe2O3 with p–n heterojunction structure

“…As depicted in Table 1, due to the load of a-Fe 2 O 3 , the specific surface area of the La 0.7 Sr 0.3 MnO 3 /a-Fe 2 O 3 (20%) increased significantly from 9.97 m 2 g -1 to 63.92 m 2 g -1 , which helps to improve its adsorption capacity. It indicates that the composite could be an efficient photocatalyst, and it will exhibit high activity owing to its high specific surface area [31].…”

Boosting Catalytic Oxidative Desulfurization Performance over Yolk–Shell Nickel Molybdate Fabricated by Defect Engineering

“…Additionally, the SSA of NMO-30 (43.5 m 2 g –1 ) is smaller than that of NMO-10 (62.7 m 2 g –1 ), while NMO-30 exhibits superior desulfurization efficiency to NMO-10, which illustrates that oxygen vacancies may play the main role in accelerating the ODS reaction. Furthermore, several similar representative ODS systems are listed for comparison (Table S2), it is observed that YS-V O -NMO can achieve ultradeep desulfurization under relatively mild reaction conditions (O/S = 5, T = 60 °C), indicating that it has appeared in the front ranks of the existing catalysts. ,− …”

“…This phenomenon may be caused by the fact that excessive H 2 O 2 added into the reaction system brings about more water, which limits the mass transfer and weakens the solubility of DBT in [OMIM]BF 4 due to the diluted extractant phase. 15 Considering that alkyl-substituted dibenzothiophenes including 4-MDBT and 4,6-DMDBT also exist in real oils, it is necessary to investigate the desulfurization efficiency of model oil systems containing them. As shown in Figure 5d, DBT and 4-MDBT can be almost removed from the oil after 70 min of reaction, while the sulfur removal of 4,6-DMDBT can only reach 94.6% under the same conditions.…”

“…14 However, it can only show high activity with the presence of an efficient catalyst during the ODS process. 15 Consequently, seeking an appropriate catalyst for ODS under mild conditions is highly desirable.…”

Batch Oxidative Desulfurization of Model Light Gasoil over a Bimetallic Nanocatalyst

“…However, due to its severe operating conditions in terms of high reaction temperature and pressure, HDS has high operating costs and is less effective in eliminating refractory sulfur compounds; hence, it may not be the optimum desulfurization process [19,20]. Recently, sophisticated technologies such as catalytic oxidative desulfurization (Cat-ODS), selective adsorption, biodesulfurization, and oxidation-extraction have been used for the production of ultralow-sulfur fuels [21][22][23]. Cat-ODS has proven to be one of the most potent recent alternatives to HDS [24,25].…”