Mercapto-Functionalized Porous Organosilica Monoliths Loaded with Gold Nanoparticles for Catalytic Application.

Hongwei Li,Liangyu Lu,Chengtao Gao,Junhui Pan,Mengyu Ma,Yuzhu Xiong,Fuping Dong

doi:10.3390/molecules24234366

Abstract

Porous organosilica monoliths have attracted much attention from both the academic and industrial fields due to their porous structure; excellent mechanical property and easily functionalized surface. A new mercapto-functionalized silicone monolith from a precursor mixture containing methyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane; and 3-mercaptopropyl(dimethoxy)methylsilane prepared via a two-step acid/base hydrolysis–polycondensation process was reported. Silane precursor ratios and surfactant type were varied to control the networks of porous monolithic gels. Gold nanoparticles were loaded onto the surface of the porous organosilica monolith (POM). Versatile characterization techniques were utilized to investigate the properties of the synthesized materials with and without gold nanoparticles. Scanning electron microscopy was used to investigate the morphology of the as-synthesized porous monolith materials. Fourier transform infrared spectroscopy was applied to confirm the surface chemistry. 29Si nuclear magnetic resonance was used to investigate the hydrolysis and polycondensation of organosilane precursors. Transmission electron microscopy was carried out to prove the existence of well-dispersed gold nanoparticles on the porous materials. Ultraviolet–visible spectroscopy was utilized to evaluate the high catalytic performance of the as-synthesized Au/POM particles

Highlights

Porous monoliths materials, including silica [1], grapheme [2], carbon nanotubes [3], and cellulose [4,5,6], have attracted much attention for versatile application due to their unique properties of low density, thermal conductivity and a high adsorption capacity [7,8,9,10]
The Porous organosilica monoliths (POM) were fabricated via a sol–gel process with methyltrimethoxysilane (MTMS), mercaptopropyltrimethoxysilane (SHTMS) and 3-mercaptopropyl(dimethoxy)methylsilane (SHDMS)
The hydrolysis-polycondensation reaction of silane co-precursors were catalyzed by the dilute acetic acid and at the same time the urea was hydrolyzed into ammonia and CO2 above 60 degrees, which raised the pH value and accelerated the condensation reaction

Summary

Introduction

Porous monoliths materials, including silica [1], grapheme [2], carbon nanotubes [3], and cellulose [4,5,6], have attracted much attention for versatile application due to their unique properties of low density, thermal conductivity and a high adsorption capacity [7,8,9,10]. Porous organosilica monoliths (POM), as one kind of molecular level organic/inorganic hybrid materials, are a class of silica-based materials containing organic groups as integral parts of their structures [11]. These hybrid materials could offer a reactive and -modified surface, large pore size and higher mechanical strength than conventional silica. Zhang et al fabricated the amine-functionalized porous organosilica monoliths with rich and adjustable pore structure via a one-step emulsion-templated process [18] This amino-POMs demonstrated excellent Cr(VI)-removal capacity with the adsorption efficiency to be 92.8% at room temperature, and good durability with the efficiency still remaining as high as 85.1% after five recycles. After the loading of gold nanoparticles, the porous nanocomposite materials showed excellent catalytic performance

Methods

Results

Conclusion