Cu@Pt catalysts prepared by galvanic replacement of polyhedral copper nanoparticles for polymer electrolyte membrane fuel cells

Polyhedral copper nanoparticles are prepared by a hydrothermal method, followed by galvanic replacement with platinum precursor in ethylene glycol to prepare bimetallic Cu@Pt electrocatalysts. The as-prepared bimetallic Cu@Pt catalyst are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and inductive coupled plasma atomic emission spectrometer. The electrochemical properties of the resulted Cu@Pt electrocatalysts with different compositions are investigated for methanol oxidation reaction and oxygen reduction reaction. The bimetallic Cu@Pt electrocatalysts with low platinum loading demonstrate high Pt utilization efficiency in fuel cell reactions. The methanol oxidation reaction mass activity for Cu@Pt-8 catalyst is 791 A g(-1), 5.1 times higher than that of the commercial Pt/C. The highest oxygen reduction reaction mass activity is found for Cu@Pt-25 (93 A g(-1) at 0.9 V versus relative hydrogen electrode), which represents 61% enhancement relative to that of a commercial Pt/C (54 A g(-1)). It is believed that the superior performance of the as-prepared bimetallic Cu@Pt catalyst is mostly attributed to the improved Pt utilization and facilitated mass transport originating from the porous structure. (c) 2019 Elsevier Ltd. All rights reserved.