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 we...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.展开更多
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 NC...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.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.21808079 and 21878121)Natural Science Foundation of Shandong Province(No.ZR2017BB029)+1 种基金China Postdoctoral Science Foundation(No.2017M610405)International Postdoctoral Exchange Fellowship Program Between Helmholtz-Zentrum Berlin für Materialien und Energie GmbH,OCPC and University of Jinan.
文摘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.
基金This work was supported by the China Postdoctoral Science Foundation （No. 2017M610405）, the Shandong Provincial Natural Science Foundation （Nos. ZR2015BM008 and ZR2017BB029） and Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.
文摘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.
