Effect of composition of Pd10-xCux (x=2, 3, 4, and 5) alloy nanoparticles on their electrocatalysis for methanol oxidation

It is well accepted that the structure, composition, and properties of solid materials are closely related with one another. In this regard, studying the relationship between the composition/structure and electrocatalytic properties can provide a great deal of insights to the design of new catalyst with enhanced electrochemical properties. In this work, Pd10-xCux nanoparticle (NP) catalysts with different Pd/Cu ratios (x = 2, 3, 4, and 5) were prepared and compared for their electrocatalytic properties for methanol oxidation reaction (MOR). Sonochemical reactions in ethylene glycol of metal precursors produced these NPs withmost of the features other than the composition the same with one another. Based on the characterization data by XRD, TEMand othermethods, x = 2 sample has the face-centered cubic (FCC) structure, x = 5 sample the body-centered cubic structure, and x = 3 and 4 samples mixtures of the two structures. The catalytic properties data show a volcano-type behavior with the change of composition, peaking at x = 3. The observed trends of electrocatalysis can be explained in terms of the composition and structure. The Pd7Cu3 catalyst shows higher activity than any of related Pd-Cu NP catalysts in the literature. (C) 2020 Elsevier B.V. All rights reserved.