Synthesis of Pd-Pt Ultrathin Assembled Nanosheets as Highly Efficient Electrocatalysts for Ethanol Oxidation

Control over composition and morphology of nanocrystals (NCs) is significant to develop advanced catalysts applicable to polymer electrolyte membrane fuel cells and further overcome the performance limitations. Here, we present a facile synthesis of Pd−Pt alloy ultrathin assembled nanosheets (UANs) by regulating the growth behavior of Pd−Pt nanostructures. Iodide ions supplied from KI play as capping agents for the {111} plane to promote 2-dimensional (2D) growth of Pd and Pt, and the optimal concentrations of cetyltrimethylammonium chloride and ascorbic acid result in the generation of Pd−Pt alloy UANs in high yield. The prepared Pd−Pt alloy UANs exhibited the remarkable enhancement of the catalytic activity and stability toward ethanol oxidation reaction compared to irregular-shaped Pd−Pt alloy NCs, commercial Pd/C, and commercial Pt/C. Our results confirm that the Pd−Pt alloy composition and ultrathin 2D morphology offer high accessible active sites and favorable electronic structure for enhancing electrocatalytic activity.