Novel polyoxometalate silica nano-sized spheres: efficient catalysts for olefin oxidation and the deep desulfurization process

authors	Nogueira, LS; Ribeiro, S; Granadeiro, CM; Pereira, E; Feio, G; Cunha-Silva, L; Balula, SS
nationality	International
journal	DALTON TRANSACTIONS
keywords	LIQUID-PHASE OXIDATION; SELECTIVE OXIDATION; HETEROGENEOUS CATALYSTS; MESOPOROUS SILICA; HYDROGEN-PEROXIDE; CATIONIC SILICA; SUBSTITUTED POLYOXOMETALATE; HIGHLY EFFICIENT; HYBRID SILICA; KEGGIN UNITS
abstract	A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn-( H2O)O-39](5-) (PW11Zn) was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, P-31 and C-13 CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.
publisher	ROYAL SOC CHEMISTRY
issn	1477-9226
year published	2014
volume	43
issue	25
beginning page	9518
ending page	9528
digital object identifier (doi)	10.1039/c3dt53444h
web of science category	Chemistry, Inorganic & Nuclear
subject category	Chemistry
unique article identifier	WOS:000337127900017