Facile Microwave-Assisted Synthesis of Concave Octahedral Pt−Cu Alloy Nanocrystals and their Electrocatalytic Properties

Well-defined concave octahedral Pt−Cu alloy nanocrystals were rapidly synthesized by reducing Pt(IV) and Cu(II) precursors simultaneously in a one-step process under microwave irradiation for 110 s in the presence of PVP and an appropriate amount of KI. The optimum molar ratio of H₂PtCl₆/CuCl₂/KI/PVP was 1/3/30/45 with a total concentration of the Pt(IV) and Cu(II) precursors of 4 mM in the reaction system. Tetraethylene glycol (TEG) was used as both a solvent and a reducing agent and the use of KI was critical to the formation of Pt−Cu alloy concave octahedral nanocrystals. In addition, microwave irradiation is advantageous to the generation of nano-alloy by promoting the simultaneous reduction of mixed metallic species. The as-prepared concave octahedral Pt−Cu alloy nanocrystals improved significantly electrocatalytic activity relative to the commercial Pt black.