Template‐ and Surfactant‐Free Room Temperature Synthesis of Pt/C and Pt−Rh/C Nanowires/Nanoparticles for Ethanol Electro‐Oxidation

Using a simple and direct method, without the use of surfactants and/or templates, it was possible to synthesize Pt−Rh nanowires, despite the formation of Pt−Rh nanoparticles as well. In addition, the addition of Rh into the Pt catalyst greatly improves the catalytic activity and stability of the material towards ethanol electro-oxidation in comparison to commercial Pt/C catalyst.

Abstract

The synthesis of Pt−Rh alloy nanowires (NWs) using straightforward methodologies remains a challenge. Here, carbon-supported Pt and Pt−Rh nanowire catalysts were synthesised by chemical reduction at room temperature, without using surfactants or templates. The method of synthesis used yielded Pt/C NWs and a mixture of nanowires with some nanoparticles for the Pt−Rh/C catalysts (characterised using XRD, TEM, EDX, XPS, and XAS). The nanoparticles form due to differences in the surface energy and atomic radius between Pt and Rh. The binary NWs are found to be more active towards ethanol oxidation than the commercial Pt/C reference catalyst. Additionally, the Pt−Rh/C NW catalyst displays a specific activity 2.5-fold higher than the Pt/C NWs and Pt/C reference catalysts after 15 min of chronoamperometric tests (at 0.5 V vs RHE). Thus, the synthesised carbon-supported Pt NWs and Pt−Rh nanowires-nanoparticles are promising alternatives for direct ethanol fuel cell anodes.

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