Issue 43, 2006

Platinum covering of gold nanoparticles for utilization enhancement of Pt in electrocatalysts

Abstract

This work attempts to enhance platinum utilization in a Pt-based electrocatalyst by the tuned covering of gold nanoparticles with small Pt entities. Reductive deposition of Pt on Au nanoparticles of two size ranges (Au-I: 10 ± 1.2 nm, Au-II: 3 ± 0.6 nm) up to different atomic Pt : Au ratios (m) was used to prepare two series of samples named Ptm⁁Au-I and Ptm⁁Au-II particles, respectively. The obtained Ptm⁁Au particles were characterized with TEM, XPS, UV-Vis and XRD techniques, and then loaded on conventional Vulcan XC-72 carbon to make Ptm⁁Au/C electrocatalysts. Cyclic voltammetry (CV) measurements showed that the electrochemical active surface area (EAS) and Pt utilization (UPt) in Ptm⁁Au/C were enhanced remarkably at m ≤ 0.2 for Ptm⁁Au-I/C or m ≤ 0.5 for Ptm⁁Au-II/C, in comparison to conventional Pt/C electrocatalyst. In particular, UPt was enhanced to nearly 100% in Ptm⁁Au-I/C catalysts at m ≤ 0.05 and in Ptm⁁Au-II/C at m ≤ 0.1. In the CV measurement of methanol electro-oxidation, the specific mass activity of Pt in Ptm⁁Au/C catalysts was found in proportional to UPt, confirming that the enhancement of Pt utilization is essential for the development of highly active Pt-based electrocatalysts. The highly dispersed Pt entities on Au nanoparticles proved to be stable during the electro-oxidation of methanol. Our study also showed that the use of smaller Au nanoparticles is advantageous for the generation of more active Pt catalyst at higher atomic Pt : Au ratios.

Graphical abstract: Platinum covering of gold nanoparticles for utilization enhancement of Pt in electrocatalysts

Article information

Article type
Paper
Submitted
18 Jul 2006
Accepted
04 Sep 2006
First published
19 Sep 2006

Phys. Chem. Chem. Phys., 2006,8, 5106-5114

Platinum covering of gold nanoparticles for utilization enhancement of Pt in electrocatalysts

D. Zhao and B. Xu, Phys. Chem. Chem. Phys., 2006, 8, 5106 DOI: 10.1039/B610269G

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