Size-Controlled Synthesis of Platinum-Copper Hierarchical Trigonal Bipyramid Nanoframes

Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size‐controlled synthesis of novel Pt–Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt–Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu. Hierarchical trigonal bipyramid nanoframes consisting of a Pt–Cu alloy with different Pt/Cu ratios are generated. Their size can be controlled in the range of 110–250 nm by varying the amount of KI in the reaction. In comparison to commercial Pt/C, these systems exhibit enhanced electrocatalytic activity in the oxidation of formic acid.