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Issue 7, 2018
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Displacement reduction routed Au–Pt bimetallic nanoparticles: a highly durable electrocatalyst for methanol oxidation and oxygen reduction

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Abstract

In this paper, a new galvanic displacement reduction (GDR) approach was demonstrated for Au–PtNPs synthesis with different Pt : Au compositions in an aqueous medium. PtNPs were initially synthesized by the reduction of H2PtCl6 using trisodium citrate and sodium borohydride. Addition of various concentrations of HAuCl4 to PtNPs leads to the formation of Au–PtNPs, which follows the GDR between Pt(0) and AuCl4 ions. The formation of Au–PtNPs was monitored by UV-vis spectroscopy by tuning the mole ratio of Pt : Au. HR-TEM images showed that the Au–PtNPs were spherical with 11 nm diameter. HR-TEM, XRD and XPS analysis showed that the formed Au–PtNPs were in the form of a core–shell structure. The colloidal Au–PtNPs were then attached on a glassy carbon (GC) electrode via a 1,6-hexanediamine linker for the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). The attachment of Au–PtNPs was further confirmed by XRD, line scanning coupled with energy-dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). The Au–PtNPs modified electrode exhibits a higher heterogeneous electron transfer rate constant of 4.12 × 10−3 cm s−1 than bare (1.01 × 10−4 cm s−1) and PtNP (1.77 × 10−4 cm s−1) modified GC electrodes. Further, the Au–PtNPs modified electrode exhibited a composition dependent activity towards the MOR and ORR. It was found that the modified electrode with a Pt : Au ratio of 1 : 0.09 shows 8 times more sensitive oxidation for the MOR when compared to a commercial Pt/C catalyst. The present Au–PtNPs catalyst exhibits a greatly enhanced catalytic activity in terms of mass activity (132 mA mg Pt−1) and excellent stability relative to the commercial Pt/C catalyst.

Graphical abstract: Displacement reduction routed Au–Pt bimetallic nanoparticles: a highly durable electrocatalyst for methanol oxidation and oxygen reduction

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Publication details

The article was received on 23 Nov 2017, accepted on 08 May 2018 and first published on 10 May 2018


Article type: Paper
DOI: 10.1039/C7SE00565B
Citation: Sustainable Energy Fuels, 2018,2, 1588-1599
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    Displacement reduction routed Au–Pt bimetallic nanoparticles: a highly durable electrocatalyst for methanol oxidation and oxygen reduction

    N. S. K. Gowthaman, B. Sinduja, S. Shankar and S. A. John, Sustainable Energy Fuels, 2018, 2, 1588
    DOI: 10.1039/C7SE00565B

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