New insights into Rh-Pt electrocatalysts with low Pt content for ethanol electro-oxidation reaction

Abstract

In this work, a new strategy to incorporate smaller amounts of Pt atoms, an active material, in an inactive Rh matrix, forming metallic nanoalloys dispersed on carbon of high surface area (Black Pearls® - BP) results in synergistic materials that have much better activity for CO₂ formation and robustness toward the ethanol oxidation reaction (EOR) in acid media when compared to the pure Pt material. The results are discussed based on crystal lattice parameter modifications focusing mainly on the lattice strain and, consequently, the electronic modification at the Pt sites. Those modifications lead to different ethanol adsorption as ethoxide termination, better long-term EOR activity, and better CO₂ production than pure Pt which normally is not observed for most electrocatalysts studied in the literature. Therefore, these are possible key materials to develop and foster direct alcohol fuel cells.