The Role of a Sn Promoter on an Anodic Pt Electrocatalyst Prepared over H2O2‐Functionalized Carbon Supports for Direct Ethanol Fuel Cell (DEFC) Applications

H₂O₂ treatment caused substantial modifications in the carbon structures. Changes in the metal-support interaction led to improved electrochemical behavior. A clear promoter effect of Sn is observed in both functionalized carbons, which shifts the CO oxidation peak to lower potentials. The current intensity of PtSn/CNT-H₂O₂ catalyst is the highest of all prepared catalysts (380 mA mg Pt⁻¹), followed by the other bimetallic catalyst supported on functionalized Vulcan carbon (296 mA mg Pt⁻¹).

Abstract

Multiwalled carbon nanotubes and Vulcan carbon were functionalized with a 30 %v/v hydrogen peroxide solution and employed as supports for Pt and PtSn catalysts prepared by the polyol method. PtSn catalysts with a Pt loading of 20 wt.% and a Pt : Sn atomic ratio equal to 3 : 1 were evaluated in the ethanol electrooxidation reaction. The effects of the oxidizing treatment on the surface area and the surface chemical nature were analyzed through N₂ adsorption, isoelectric point, and temperature-programmed desorption measurements. Results showed that the H₂O₂ treatment affects the surface area of the carbons to a great extent. Characterization results indicated that the performance of the electrocatalysts strongly depends both on the presence of Sn and on the support functionalization. PtSn/CNT−H₂O₂ electrocatalyst displays a high electrochemical surface area and enhanced catalytic activity for ethanol oxidation in comparison to other catalysts in the present study.

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