Issue 42, 2015

Kinetic analysis of the reduction of 4-nitrophenol catalyzed by Au/Pd nanoalloys immobilized in spherical polyelectrolyte brushes

Abstract

We present a detailed study of the catalytic activity of Au/Pd nanoalloys with Au : Pd molar ratio 75 : 25 synthesized using spherical polyelectrolyte brushes (SPB) as carrier system. The reduction of 4-nitrophenol (Nip) by sodium borohydride (BH4) has been used as a model reaction. This reaction proceeds in two steps: 4-nitrophenol is first reduced to 4-hydroxylaminophenol which in a second step is reduced to the final product 4-aminophenol. Both steps of the reaction proceed on the surface of the nanoparticles (Langmuir–Hinshelwood-mechanism). We use this model to analyze the experimental data obtained by catalysis with the Au/Pd-nanoalloys. Good agreements between theory and experiments were found up to 30% conversion of Nip. The kinetic parameters were compared with the data derived from neat Au and Pd nanoparticles immobilized in the same SPB carrier system. The addition of 25% molar ratio of Pd to the nanoalloys increases the reaction rate of the first step nearly 10 times compared with that of SPB-Au and 60 times compared with that of SPB-Pd. Analysis of the nanoalloy by high-resolution transmission electron microscopy suggests that the surface defects of the nanoalloys play an important role for the enhanced catalytic activity.

Graphical abstract: Kinetic analysis of the reduction of 4-nitrophenol catalyzed by Au/Pd nanoalloys immobilized in spherical polyelectrolyte brushes

Supplementary files

Article information

Article type
Paper
Submitted
27 Jan 2015
Accepted
11 Mar 2015
First published
11 Mar 2015

Phys. Chem. Chem. Phys., 2015,17, 28137-28143

Author version available

Kinetic analysis of the reduction of 4-nitrophenol catalyzed by Au/Pd nanoalloys immobilized in spherical polyelectrolyte brushes

S. Gu, Y. Lu, J. Kaiser, M. Albrecht and M. Ballauff, Phys. Chem. Chem. Phys., 2015, 17, 28137 DOI: 10.1039/C5CP00519A

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