Trimetallic Pd@PtxAu1−x Core-Shell Nanocubes with Enhanced Selectivity toward H2O2 for the Oxygen Reduction Reaction

We report a versatile method based on seed-mediated growth for the facile synthesis of trimetallic Pd@PtxAu1−x core-shell nanocubes. By simply varying the feeding ratio between the Pt(II) and Au(III) precursors, the atomic ratio of Pt to Au in the shell and thereby the ensemble state of Pt atoms on the surface can be tuned to control the binding configuration of O2 molecules. Specifically, discrete Pt atoms on the surface promote the adsorption of O2 molecules in the Pauling configuration to enhance the catalytic selectivity of the nanoparticles toward H2O2 via the two-electron oxygen reduction reaction, with the Pd@Pt0.025Au0.975 nanocubes showing selectivity as high as 91% at 0.45 VRHE. This work offers a viable means to augment the electrocatalytic performance of alloy nanocrystals by controlling their surface compositions.