Vertex-Type Engineering of Pt-Cu-Rh Heterogeneous Nanocages for Highly Efficient Ethanol Electrooxidation.

Abstract

Mastery over the architecture and elemental distribution of metal nanocrystals at the nanoscale can effectively tailor and improve their catalytic properties. Herein, the vertex-type-selective growth of metallic nanohorns on a central nanocrystal is constructed via a one-pot solvothermal synthesis, despite the fact that the site-selective epitaxy of the second phase proceeds on all the vertices of the seeds. The prepared vertex-type-selective Pt-Cu-Rh heterogeneous nanocages (HNCs) are composed of a Rh-decorated Pt-Cu rhombic dodecahedral nanocage and six Pt-Cu-Rh nanohorns protruding from the {100} rather than the {111} vertices of rhombic dodecahedron. Impressively, the Pt-Cu-Rh HNCs exhibit 8.1 times higher specific and 6.8 times higher mass activity toward the ethanol oxidation reaction under acidic conditions than commercial Pt/C catalysts. Besides, the peak potential for CO oxidation on Pt-Cu-Rh HNCs (370.4 mV vs SCE) is 182.0 mV more negative than that on Pt/C, indicating the dramatically enhanced CO tolerance. The excellent electrocatalytic property is attributed to the synergistic effect between Pt, Cu, and Rh components, high specific surface area of nanocages and nanohorns, as well as abundant concave/convex sites and various high-index facets around the surface.