Rare-earth modified Pt-Sn catalysts obtained via bromide anion exchange for enhanced ethanol electrooxidation in alkaline medium

Pt-Sn/C has been widely reported as an anode catalyst in direct ethanol fuel cell (DEFC). However, this bimetallic catalyst often results in the production of a four-electron reaction product (acetate) instead of 12 electrons required for complete ethanol oxidation. In this work, a surfactant-free bromide anion exchange (BAE) method was used for the first time to prepare rare-earth (La, Ce, Pr, and Eu) modified Pt-Sn electrocatalysts for promoting the C-C bond cleavage. Among the synthesized nanomaterials, Pt-Sn-Ce/C exhibited the highest current density and good stability in alkaline medium. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface properties of the synthesized materials and correlate them with electrochemical characterizations to enhance their activity towards ethanol oxidation reaction (EOR). The in situ Fourier transform infrared (FTIR) spectroscopy investigations provided evidence of similar EOR pathways for Pt-Sn and rare-earth modified bimetallic anodes. The presence of the cocatalysts promoted higher current density during the EOR, especially for Pt-Sn-Ce/C.