One-pot synthesis of Pt-Cu bimetallic nanocrystals with different structures and their enhanced electrocatalytic properties

摘要

Shape-controlled synthesis of Pt-Cu alloy nanocrystals (NCs) with unique geometries is of great importance in the rational design and deterministic synthesis of highly active electrocatalysts. Herein, Pt-Cu alloy NCs with concave octahedron (COH), porous octahedron (POH), yolk-shell (YSH), and nanoflower (NOF) structures were fabricated by altering the sequential reduction kinetics in a one-pot aqueous phase. The effect of the reaction kinetics on the formation of Pt-Cu bimetallic NCs with different morphologies was analyzed quantitatively. The concentrations of glycine and metal cation are demonstrated to play a key role in the reduction of Pt(IV) and Cu(II) ions; these significantly affected the morphology of Pt-Cu NCs. These Pt-Cu alloy NCs exhibit substantially enhanced catalytic activity and durability for methanol and formic acid oxidation compared to the commercial Pt/C catalyst. Specifically, the COH and NOF Pt-Cu NCs with more step atoms, intragranular dislocations, and protrusions showed superior electrochemical properties than those of POH and YSH Pt-Cu NCs. The structure-property relationship between the Pt-Cu NCs and their electrochemical performances was also investigated in depth.