Altering the electronic structure and surface chemical environment of Pt{100} facets via synergizing with Ir species for enhanced oxygen-reduction activity and stability.

Shape-controlled metal-based nanomaterials provide a special platform to regulate the surface physicochemical properties for optimizing the electrocatalytic performance, due to their homogeneously arranged surface atomic structures. Accordingly, owing to the solely {100} facets-ended surfaces, highly uniform Pt nanocubes (NCs) are utilized in this study, to probe the effects of synergizing with Ir species (a very effective metal for various electrocatalysis) on the electrocatalytic performance for the oxygen reduction reaction (ORR). Electrochemical results present that carbon-supported Pt 1 Ir 1 NCs with surface Ir–O species (Pt 1 Ir 1 –O NCs/C) have much enhanced electrocatalytic activity and electrochemical stability than both Pt NCs/C and commercial Pt/C. Physicochemical characterization and theoretical calculation analyses further elucidate the mechanism of the improved electrocatalytic performance: the strong electronic interaction between Pt and Ir, the lowered d -band center of the surface metal atoms, and especially the synergistic effect induced by the surface Ir–O species. This study not only develops a highly active and stable ORR electrocatalyst, but also demonstrates an effective and universal research paradigm to explore the surface engineering effects on the electrocatalytic performance, which can be further applied in other crystalline facets for other (electro)catalytic reactions. Alloying with Ir evidently enhances the oxygen-reduction performance of the {100} facets-enclosed Pt nanocubes, through the modified electronic structure and especially the local O–O repulsion caused by the surface Ir–O species. [Display omitted] • Small and highly uniform Pt–Ir alloy NCs with surface Ir–O species are synthesized. • Pt–Ir NCs exhibit evidently higher ORR performance than both Pt NCs and Pt/C. • Ir tunes the electronic structure of Pt{100} facets for lowering the d -band center. • Ir–O species alter the surface chemical environment to form the O–O repulsion. [ABSTRACT FROM AUTHOR]