Electro-Oxidation of Ethanol Using Pt₃Sn Alloy Nanoparticles

Abstract

Ethanol represents a promising liquid energy source for fuel cells. The development of direct ethanol fuel cells (DEFCs) is however challenged by the lack of efficient electrocatalysts for the complete oxidation of ethanol to CO2. Here we report the investigation of ethanol electro-oxidation on monodisperse and homogeneous Pt3Sn alloy nanoparticles. Electrochemical studies were conducted comparatively on the Pt3Sn nanoparticles supported on carbon (Pt3Sn/C), a commercial Pt/C catalyst, as well as KOH-treated Pt3Sn/C with the surface tin species removed. Our studies reveal the dual role of Sn in the EOR electrocatalysis on Pt3Sn/C: the surface Sn, likely in the form of tin oxides, enhances the oxidation of *CHx intermediate to *CO; the subsurface metallic Sn weakens the binding of *CO and facilitates its oxidative removal. A synergy of these two roles, plus the presence of Pt surface sites capable of cleaving the C–C bond, gives rise to the enhanced complete oxidation of ethanol.