Structure-engineered platinum-based nanoframes (NFs) at the atomic level can effectively improve the catalytic performance for fuel cells and other heterogeneous catalytic fields. We report herein, a microwave-assisted wet-chemical method for the preparation of platinum-copper-cobalt NFs with tunable defect density and architecture, which exhibit enhanced activity and durability towards the electro-oxidation reactions of methanol (MOR) and formic acid (FAOR). By altering the reduction/capping agents and thus the nucleation/growth kinetics, trimetallic platinum-copper-cobalt hexapod NFs with different density high-index facets are achieved. Especially, the rough hexapod nanoframes (rh-NFs) exhibit excellent specific activities towards MOR and FAOR, 7.25 and 5.20 times higher than those of benchmark Pt/C, respectively, along with prolonged durability. The excellent activities of the rh-NFs are assigned to a synergistic effect, including high density of defects and high-index facets, suitable d-band center, and open-framework structure. This synergistic working mechanism opens up a new way for enhancing their electrocatalytic performances by increasing defect density and high-index facets in open-framework platinum-based NFs.

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.