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

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‐Y2O3 and Pt‐Gd2O3 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‐Y2O3/C and Pt‐Gd2O3/C catalysts towards the oxygen reduction reaction (ORR) is studied in a 0.5 M H2SO4 electrolyte. The surface and mass specific activities of the Pt‐Y2O3/C catalyst towards the ORR at 0.9 V (vs. the reversible hydrogen electrode, RHE) are (54.3±1.2) μA cm−2Pt and MA=(23.1±0.5) mA mg−1Pt, 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‐Gd2O3/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−2Pt, and a mass specific activity (MA) of about (18.2±0.5) mA mg−1Pt at 0.9 V (vs. RHE). The enhancement of the ORR kinetics on the Pt‐Y2O3/C and heat‐treated Pt‐Gd2O3/C catalysts could be associated with the formation of platinum NPs presenting modified surface properties. Carbon‐supported nanoparticles (NPs) are synthesized by a water‐in‐oil chemical route. The Y‐ and Gd‐modified Pt NPs show an enhanced electrocatalytic activity for the oxygen reduction reaction (ORR). X‐ray diffraction and X‐ray photoelectron spectroscopy studies reveal no evidence of alloy formation. The enhancement of the ORR kinetics on Pt‐Y/C and heat‐treated Pt‐Gd/C catalysts could be associated with the surface modification of Pt NPs by rare‐earth‐element oxides.