Roles of the structural defects and the combined acidity of H₃PW₁₂O₄₀/Zr-MCM-41 catalysts in ultralow sulfur diesel production

Abstract

The oxidative desulfurization (ODS) has been become an important technical route for the production of ultralow sulfur fuel. This work focused on the deep understanding the roles of structural defects,...

Titanium dioxide-modified nanosized TS-1 zeolite-supported phosphotungstic acid as a catalyst for deep catalytic oxidative desulfurization of fuel oil

“…41,42 Many researchers have reported ODS reactions catalyzed by HPW. 43,44 De Luna and co-workers investigated the ODS rate of DBT using HPW as a catalyst and H 2 O 2 as an oxidant; the system can reach a high sulfur conversion (100.0%) at 60 1C after 40 min. 45 Wan's group studied ODS activities of BT and DBT using POMs/H 2 O 2 systems and a phase-transfer agent with the assistance of vigorous mixing and ultrasound.…”

Ultralow sulfur diesel production with defective 12-molybdophosphoric acid polyoxometalate

“…15. It has been reported that the combination of B and L acid sites benefits the oxygen transfer and sulfur oxidation in the H 3 PW 12 O 40 /Zr-MCM-41 catalysts, 29 where some B acid sites are located near L acid sites as neighbors or as adjacent combined B–L acid site pairs. Because DBT adsorption and peroxometallic and superoxometallic species formation occur on the Lewis acid centers, only in the case when a B acid site is located near this L acid site, can they participate in the ODS reaction.…”

“…It has been reported that heteropolyacids containing Mo or W with lacunary Keggin units are effective for the ODS reaction, due to their strong acidic properties and tunable redox properties. 15,28,29 When heteropolyacids are mixed with an oxidant such as hydrogen peroxide, they can be transformed into polyoxometalates, which are very active for the oxidation of many organic compounds. [28][29][30][31][32] The drawbacks of heteropolyacids include a low surface area (o5 m 2 g À1 ) and low accessibility.…”

“…15,28,29 When heteropolyacids are mixed with an oxidant such as hydrogen peroxide, they can be transformed into polyoxometalates, which are very active for the oxidation of many organic compounds. [28][29][30][31][32] The drawbacks of heteropolyacids include a low surface area (o5 m 2 g À1 ) and low accessibility. To overcome these drawbacks, dispersion of heteropolyacids on carriers such as TiO 2 , SiO 2 , MIT-101 and others has proven to be a sound strategy for obtaining active catalysts for ODS reactions.…”