Pd-M/C (M = Pd, Cu, Pt) Electrocatalysts for Oxygen Reduction Reaction in Alkaline Medium: Correlating the Electronic...

The increasing global needs for clean and renewable energy have fostered the design of new and highly efficient materials for fuel cells applications. In this work, Pd-M (M = Pd, Cu, Pt) and Pt nanoparticles were prepared by a green synthesis method. The carbon-supported nanoparticles were evaluated as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium. A comprehensive electronic and structural characterization of these materials was achieved using X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Their electrochemical properties were investigated by cyclic voltammetry, while their activities for the ORR were characterized using steady-state polarization experiments. The results revealed that the bimetallic nanoparticles consist of highly crystalline nanoalloys with size around 5 nm, in which the charge transfer involving Pd and M atoms affects the activity of the electrocatalysts. Additionally, the samples with higher ORR activity are those whose d-band center is closer to the Fermi level.