Tailoring the morphology of Pt3Cu1 nanocrystals supported on graphene nanoplates for ethanol oxidation

Abstract

In the search for alternatives to conventional Pt electrocatalysts, we synthesized a series of graphene nanoplate (GNP)-supported Pt₃Cu₁ nanocrystals (NCs), possessing almost the same composition but different morphologies to probe their electrochemical properties as a function of morphology for the ethanol oxidation reaction. The morphology of the Pt₃Cu₁ catalysts could be systematically evolved from dendritic (D-Pt₃Cu₁/GNPs) to wire-like (W-Pt₃Cu₁/GNPs) and spherical (Pt₃Cu₁/GNPs) by only varying pH of the reaction solution. The as-prepared Pt₃Cu₁ catalysts were subsequently characterized using a suite of techniques including transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS) to verify not only their morphologies and chemical compositions but also the incorporation of Cu into the Pt lattice, as well as physical structure and integrity. Gratifyingly, the three Pt₃Cu₁ catalysts exhibited superior electrocatalytic properties for the ethanol oxidation compared to the monometallic Pt/GNPs and Pt/C-JM (Johnson Matthey), with the activities, durabilities and anti-poisonous abilities following the order Pt₃Cu₁/GNPs < W-Pt₃Cu₁/GNPs < D-Pt₃Cu₁/GNPs.