Yttrium Oxide/Gadolinium Oxide-Modified Platinum Nanoparticles as Cathodes for the Oxygen Reduction Reaction

Abstract Rare‐earth‐element (Y, Gd) modified Pt nanoparticles (NPs) supported on a carbon substrate (Vulcan XC‐72) are synthesized via a water‐in‐oil chemical route. In both cases, X‐ray diffraction (XRD) measurements show the non‐formation of an alloyed material. Photoemission spectroscopy (XPS) results reveal that Y and Gd are oxidized. Additionally, no evidence of an electronic modification of Pt can be brought to light. Transmission electron microscopy (TEM) studies indicate that Pt‐Y 2 O 3 and Pt‐Gd 2 O 3 particles are well dispersed on the substrate—and that their average particle sizes are smaller than the Pt‐NP sizes. The catalytic activity of the Pt‐Y 2 O 3 /C and Pt‐Gd 2 O 3 /C catalysts towards the oxygen reduction reaction (ORR) is studied in a 0.5 M H 2 SO 4 electrolyte. The surface and mass specific activities of the Pt‐Y 2 O 3 /C catalyst towards the ORR at 0.9 V (vs. the reversible hydrogen electrode, RHE) are (54.3±1.2) μA cm −2 Pt and MA=(23.1±0.5) mA mg −1 Pt , respectively. These values are 1.3‐, and 1.6‐fold higher than the values obtained with a Pt/C catalyst. Although the as‐prepared Pt‐Gd 2 O 3 /C catalyst has a lower catalytic activity for the ORR compared to Pt/C, the heat‐treated sample shows a surface specific activity of about (53.0±0.7) μA cm −2 Pt , and a mass specific activity (MA) of about (18.2±0.5) mA mg −1 Pt at 0.9 V (vs. RHE). The enhancement of the ORR kinetics on the Pt‐Y 2 O 3 /C and heat‐treated Pt‐Gd 2 O 3 /C catalysts could be associated with the formation of platinum NPs presenting modified surface properties.