Synthesis of Pd3Co1@Pt/C Core-Shell Catalysts for Methanol-Tolerant Cathodes of Direct Methanol Fuel Cells

A composite Pd‐based electrocatalyst consisting of a surface layer of Pt (5 wt. %) supported on a core Pd3Co1 alloy (95 wt. %) and dispersed as nanoparticles on a carbon black support (50 wt. % metal content) was prepared by using a sulphite‐complex route. The structure, composition, morphology, and surface properties of the catalyst were investigated by XRD, XRF, TEM, XPS and low‐energy ion scattering spectroscopy (LE‐ISS). The catalyst showed an enrichment of Pt on the surface and a smaller content of Co in the outermost layers. These characteristics allow a decrease the Pt content in direct methanol fuel cell cathode electrodes (from 1 to 0.06 mg cm−2) without significant decay in performance, due also to a better tolerance to methanol permeated through the polymer electrolyte membrane. A Pd3Co1 core catalyst covered by a thin Pt shell allows a significant improvement in the cost‐effectiveness of direct methanol fuel cells. The synergistic effect between Pt and the PdCo alloy results in a three‐fold better performance (considering the cathode cost) than its Pt‐based counterpart. The low content of Pt compensates the performance gap of Pd, and the presence of the latter enhances the tolerance to methanol (see figure).