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Bimetallic Ag–Au/SiO2 catalysts: Formation, structure and synergistic activity in glucose oxidation

Paper ID Volume ID Publish Year Pages File Format Full-Text
39751 45834 2014 9 PDF Available
Title
Bimetallic Ag–Au/SiO2 catalysts: Formation, structure and synergistic activity in glucose oxidation
Abstract

•Alloyed AgAu NPs of various Ag/Au molar ratios were formed by colloidal methods.•Synergistic effect in glucose oxidation activity was observed at Ag/Au < 1.•Mechanism is advised based on the results and literature data.

SiO2 supported Ag–Au bimetallic catalysts were prepared by sol adsorption method with 10/90, 20/80, 33/67, and 50/50 Ag/Au molar ratios. Reduction of HAuCl4 in Ag sol resulted in alloyed Ag–Au colloid particles and that structure remained after calcination and reduction treatment. The alloy structure of the catalysts was confirmed by UV–visible spectroscopy and high resolution transmission electron microscopy. The Au–Ag bimetallic effect and its dependence on the Ag/Au molar ratio was studied in glucose oxidation where synergistic activity increase was observed compared to the Au/SiO2 reference sample in the case of the bimetallic samples with less than Ag/Au = 50/50 molar ratio. The Ag/SiO2 was inactive at the same conditions. The Ag/Au surface atomic ratios – calculated by X-ray photoelectron spectroscopy (XPS) – were slightly higher than in the bulk—determined by prompt gamma activation analysis (PGAA). The higher activity of the bimetallic samples is suggested to be caused by the improved O2 activating ability provided by Ag sites. The further increase of Ag loading above the optimal concentration may dilute or cover the Au to such an extent that the number of gold ensembles necessary for glucose activation decreases deteriorating the activity.

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Keywords
Ag–Au nanoparticle; Glucose oxidation; Synergistic effect; Bimetallic catalyst; Gold catalysis
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Bimetallic Ag–Au/SiO2 catalysts: Formation, structure and synergistic activity in glucose oxidation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 479, 5 June 2014, Pages 103–111
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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