Maximizing the Catalytic Performance of Pd@Au_xPd_1−<i>x</i> Nanocubes in H₂O₂ Production by Reducing Shell Thickness to Increase Compositional Stability

Abstract We report a simple route based upon seed‐mediated growth to the synthesis of Pd@Au x Pd 1− x (0.8≤ x ≤1) core–shell nanocubes. Benefiting from the well‐defined {100} facets and an optimal Au/Pd ratio for the surface, the nanocubes bearing a shell made of Au 0.95 Pd 0.05 work as an efficient electrocatalyst toward H 2 O 2 production, with high selectivity of 93–100 % in the low‐overpotential region of 0.4–0.7 V. When the Au 0.95 Pd 0.05 alloy is confined to a shell of only three atomic layers in thickness, the electrocatalyst is able to maintain its surface structure and elemental composition, endowing continuous and stable production of H 2 O 2 during oxygen reduction at a high rate of 1.62 mol g (Pd+Au) −1 h −1 . This work demonstrates a versatile route to the rational development of active and durable electrocatalysts based upon alloy nanocrystals.