Strain-Controlled\nGalvanic Synthesis of Platinum Icosahedral\nNanoframes and Their Enhanced Catalytic Activity toward Oxygen Reduction

The unique strain distribution on the surface of a Pd\nicosahedral\nnanocrystal is leveraged to control the sites for oxidation and reduction\ninvolved in the galvanic replacement reaction. Specifically, Pd is\noxidized and dissolved from the center of each {111} facet due to\nits tensile strain, while the Pt(II) precursor adsorbs onto the vertices\nand edges featuring a compressive strain, followed by surface reduction\nand conformal deposition of the Pt atoms. Once the galvanic reaction\nis initiated, the {111} facets become more vulnerable to oxidation\nand dissolution, as the vertices and edges are protected by the deposited\nPt atoms. The site-selected galvanic reaction naturally results in\nthe formation of Pt icosahedral nanoframes covered by compressively\nstrained {111} facets, which show enhanced catalytic activity and\ndurability toward oxygen reduction relative to commercial Pt/C.