Mesoporous nanosilica-supported polyoxomolybdate as catalysts for sustainable desulfurization

This work was partly funded through the projects REQUIMTE-LAQV, POCI-01-0145-FEDER-007265 [FCT (Fundacao para a Ciencia e a Tecnologia) Ref. UID/QUI/50006/2013] and CICECO -Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The FCT and the European Union are acknowledged for post-doctoral grants to C.M.G. (SFRH/BPD/109253/2015) and L.C.S. (SFRH/BPD/111899/2015) co-funded by MCTES and the European Social Fund through the program POPH of QREN.Mesoporous silica nanoparticles (MSNs) strategically functionalized were used to immobilize a homogeneous polyoxomolybdate catalyst [PMo 12 O 40 ] 3- (PMo 12 ), active but unstable. The PMo 12 @TBA-MSN composite (where TBA refers to surface-tethered tributylammonium groups) conferred high stability to the polyoxomolybdate catalytic center and displayed an increase in efficiency for the oxidative desulfurization (ECODS) of a diesel simulant under sustainable conditions (using H 2 O 2 as oxidant and an ionic liquid, [BMIM]PF 6 , as solvent). Continuous reuse of the catalyst and ionic liquid solvent in consecutive ECODS cycles was successfully performed, avoiding the production of residual wastes. The performance of the PMo 12 @TBA-MSN catalyst improved upon its reuse, leading to complete desulfurization of a multicomponent model diesel containing benzothiophene derivatives after just 1 h of the catalytic stage of the process. The robust nature of the supported catalyst was indicated by characterization of the recovered solid which showed retention of the structural and chemical integrities.authorsversionpublishe