Ultrafine nanoporous Cu–Pd alloys with superior catalytic activities towards electro-oxidation of methanol and ethanol in alkaline media

Abstract

In this work, the dealloying of ternary Mg–Cu–Pd alloys and formation of nanoporous Cu–Pd alloys have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy dispersive X-ray (EDX) analysis and electrochemical measurements. The results show that the Pd addition has a significant influence on the phase constitution and dealloying process of the rapidly solidified Mg–Cu–Pd alloys. Ultrafine nanoporous Cu–Pd alloy nanostructures with ligaments/channels of less than 10 nm can be obtained in the as-dealloyed samples. The dealloying mechanism and formation of ultrafine nanoporous structures have been rationalized by electrochemical activity measurements and surface diffusion of Cu/Pd adatoms. These ultrafine nanoporous Cu–Pd alloys exhibit high specific surface areas and superior electrocatalytic performance towards electro-oxidation of methanol and ethanol in alkaline media. The present findings provide a facile dealloying route to fabricate nanoporous Cu–Pd alloy electrocatalysts for applications in direct alcohol fuel cells.