Controllable Preparation of Monodisperse Mesoporous Silica from Microspheres to Microcapsules and Catalytic Loading of Au Nanoparticles

Abstract

A unique structural transition from pomegranate-like monodisperse mesoporous silica microspheres (M-MSMs) with tunable mesopores to mesoporous silica microcapsules has been reported. The unique evolution occurred together with varying the cross-linking degrees (CLDs) of templates. Herein, using monodisperse sulfonated cross-linked polystyrene (S-CLPS) as templates, S-CLPS/ SiO 2 composite microspheres were synthesized by the sol−gel method. Subsequently, the templates were removed by calcination to obtain the M-MSMs or microcapsules. The pore sizes of M-MSMs could be tailored from 3.2 to 7.4 nm by facilely varying the CLDs from 0.5 to 20%. Interestingly, mesoporous silica microcapsules were gradually formed when the CLDs were beyond 20%. Meanwhile, the specific surface area also could be adjusted by this strategy without hardly affecting the monodispersity, and the specific surface area increased to 391.9 m 2 /g. Significantly, Au@M-MSM was prepared by supporting Au nanoparticles (NPs) on M-MSM and used as nanocatalysts to reduce 4-nitrophenol (4-NP). The ultrathin shell and interconnected three-dimensional (3D) porous structure of M-MSMs can increase the mass transfer and protect the Au NPs from leakage, which reveals high recyclability and high conversion (>95%) after 10 regeneration−catalysis cycles. This approach provides a nanotechnology platform for the preparation of mesoporous silica materials with different microstructures, which will have enormous potential in practical applications involving different molecular sizes.

CoFe Nanoparticle-Decorated Reduced Graphene Oxide for the Highly Efficient Reduction of 4-Nitrophenol

“…Due to the highly toxic, carcinogenic, and teratogenic properties, 4-NP is well-known as one kind of the “priority pollutants” . Many kinds of catalysts have been developed for the catalytic degradation of 4-NP to 4AP, including Pd–Ni nanowires, Pt–Fe 3 O 4 , Pt–Cu bimetallic NPs, Au-Silica, Pd cubes, Au–SnO 2 , and so on. ,− Therefore, the catalytic properties of the CoFe/RGO nanocomposites were evaluated by the reduction of 4-NP to 4-AP. The reaction kinetic parameters were determined from the time-dependent spectra of the solution.…”

In Situ Growth of ZIF-8 Nanocrystals on the Pore Walls of 3D Ordered Macroporous TiO2 for a One-Pot Cascade Reaction

“…First, the cross-linked polystyrene (CLPS) microspheres were prepared according to the previous report [41]. Then, the product was collected by centrifugation and finally dried in a dryer to obtain CLPS colloidal crystal template (CCT).…”

Functionalisation of alkali-resistant nanoporous glass via Au nanoparticle decoration using alkaline impregnation: catalytic activity for CO removal

“…Hence, the concerted use of nanoporous materials and nano-metal particles with catalytic functions holds great promise for effective air purication and gas sensing. [1][2][3][4][5][6][7][8][9][10][11][12][13] Supported Au nanoparticles on oxides exhibit various catalytic activities. [14][15][16][17] Extensive research efforts have highlighted the crucial role of the heterojunction between the oxide support and Au nanoparticles in catalytic functions.…”