Divanadium‐Substituted Phosphotungstate Supported on Magnetic Mesoporous Silica Nanoparticles as Effective and Recyclable Catalysts for the Selective Oxidation of Alcohols

Abstract

A new magnetically recyclable catalyst (Fe3O4@mSiO2/NH‐PV2W) was fabricated by immobilizing divanadium‐substituted Keggin phosphotungstic acid H5PV2W10O40 on mesoporous‐silica‐coated Fe3O4 core–shell nanoparticles by a facile procedure. The magnetic core–shell nanoparticles were prepared by coating a thin mesoporous silica shell directly on pristine magnetic Fe3O4 and functionalized with amino radicals simultaneously. Then the active H5PV2W10O40 was immobilized on the mesoporous silica shell of the Fe3O4 core–shell nanoparticles. The obtained catalyst was characterized by using SEM, TEM, IR spectroscopy, XRD, N2 sorption–desorption, and magnetometry. The catalytic properties were evaluated for a series of alcohols that were oxidized selectively to the corresponding aldehydes or ketones using hydrogen peroxide as the oxidant. The results show that H5PV2W10O40‐loaded mesoporous silica‐coated Fe3O4 catalyst presents high catalytic activities with 98 % conversion of benzyl alcohol and 99 % selectivity to benzaldehyde. After the reaction, the catalyst could be separated easily with an external magnetic field, and the recovered catalyst could be reused at least five times without any loss of catalytic activity.

In Situ Depositing Ag NPs on PDA/SiW11V Co‐encapsulated Fe3O4@TiO2 Magnetic Microspheres as Highly Efficient and Durable Visible‐light‐driven Photocatalysts

“…The FT‐IR spectra of as‐prepared Fe 3 O 4 , Fe 3 O 4 @TiO 2 , Fe 3 O 4 @TiO 2 @PDA/SiW 11 V, Fe 3 O 4 @TiO 2 @PDA/SiW 11 V−Ag samples are compared in Figure 2, as well SiW 11 V and PDA. For the pristine Fe 3 O 4 magnetite core, the band at 584 cm −1 is assigned to the stretching vibration of Fe−O bonds (Figure 2a) [17] . After introducing TiO 2 shell, the absorption region extends to 954 cm −1 owing to Ti−O−Ti stretching vibrations (Figure 2b) [3e] .…”

Recent Advances in the Synthesis, Surface Modifications and Applications of Core‐Shell Magnetic Mesoporous Silica Nanospheres

“…Li et al [149] [141] tal results showed that the FST microspheres had high photocatalytic activity under ultraviolet light, and the degradation rate of methyl orange reached 95.0%. Then Li et al further prepared a new hollow network magnetic Fe 3 O 4 /SiO 2 /mTiO 2 (FSmT) composite microsphere photocatalyst by using network Fe 3 O 4 as the magnetic layer, dense SiO 2 layer as the electronic barrier and mesoporous TiO 2 as the active layer.…”

Magnetic crosslinked copoly(ionic liquid) nanohydrogel supported palladium nanoparticles as efficient catalysts for the selective aerobic oxidation of alcohols

“…different organic transformations [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. However, to date, few magnetite nanoparticles supported palladium catalysts have been prepared and successfully used in the aerobic oxidation of alcohols.…”