Characterization and electrocatalytic activity of Pt-M (M=Cu, Ag, and Pd) bimetallic nanoparticles synthesized by pulsed plasma discharge in water

The synthetic approach for electrocatalysts is one of the most important methods of determining electrocatalytic performance. In this work, we synthesized Pt and Pt-M (M=Cu, Ag, and Pd) bimetallic nanoparticles using a pulsed plasma discharge in water. A morphological investigation revealed that the as-synthesized Pt and Pt-M bimetallic nanoparticles constituted a nanochain network structure interconnected with primary nanoparticles of 4-6 nm in size, and the nanochains grew from the primary nanoparticles via the oriented attachment. The Z-contrast, EDX line scanning, and XRD analysis confirmed that the Pt was alloyed with M without elemental segregation or phase segregation. Furthermore, it was found that the composition difference was dependent on the electrode temperature determined by the power density and thermal parameters. The electrochemical results revealed that the electrocatalytic activity, stability, and durability of the Pt-Ag bimetallic nanoparticles were superior with respect to the methanol oxidation reaction, which could be attributed to the downshift of the d-band center via electronic modification.