On the Stabilization of Gold Nanoparticles over Silica-Based Magnetic Supports Modified with Organosilanes

• Published in: Chemistry : a European journal Vol. 17; no. 16; pp. 4626 - 4631
• Main Authors: Oliveira, Rafael L., Zanchet, Daniela, Kiyohara, Pedro K., Rossi, Liane M.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 11.04.2011; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Chemical reactions; Chemistry; Fine structure; Gold; Nanoparticles; organosilanes; silica; Silicon dioxide; Stabilization; Surface chemistry; X-ray absorption spectroscopy; X-rays
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201002251

The immobilization of gold nanoparticles (Au NPs) on silica is made possible by the functionalization of the silica surfaces with organosilanes. Au NPs could only be stabilized and firmly attached to silica‐support surfaces that were previously modified with amino groups. Au NPs could not be stabilized on bare silica surfaces and most of the NPs were then found in the solution. The metal–support interactions before and after the Au NP formation, observed by X‐ray absorption fine structure spectroscopy (XAFS), indicate a stronger interaction of gold(III) ions with amino‐modified silica surfaces than with the silanol groups in bare silica. An amino‐modified, silica‐based, magnetic support was used to prepare an active Au NP catalyst for the chemoselective oxidation of alcohols, a reaction of great interest for the fine chemical industry. Catch me if you can! The immobilization of gold nanoparticles (Au NPs) on silica was made possible by the functionalization of the silica surfaces with organosilanes (see scheme). Using this principle, an amino‐modified, silica‐based, magnetic support was used to prepare an easily recoverable and very active Au NP catalyst for the chemoselective oxidation of alcohols.