Composition-dependent electrocatalytic activity of AuPd alloy nanoparticles prepared via simultaneous sputter deposition into an ionic liquidElectronic supplementary information (ESI) available: Absorption spectra, TEM images, XANES spectra and Pd K-edge EXAFS of AuPd particles in BMI-TFSA, and AFM images and N 1s XPS spectra of AuPd particles immobilized on HOPG. See DOI: 10.1039/c3cp50816a

• Main Authors: Hirano, Masanori, Enokida, Kazuki, Okazaki, Ken-ichi, Kuwabata, Susumu, Yoshida, Hisao, Torimoto, Tsukasa
• Format: Journal Article
• Language: English
• Published: 24.04.2013
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp50816a

Homogeneously alloyed bimetallic particles of AuPd with an average size of ca. 2 nm were successfully prepared by simultaneous sputter deposition of Au and Pd in an ionic liquid in the absence of any additional stabilizing agents. The chemical composition of the AuPd alloy was tunable depending on the area fraction of Au plates in the Au-Pd binary targets for sputtering. The particles were immobilized on an HOPG surface by heat treatment along with the increase in the average size of particles from ca. 2 nm to ca. 7 nm. Ionic liquid species adsorbed on the as-prepared AuPd nanoparticle films on HOPG caused the prevention of electrocatalytic reactions, but repetition of potential sweep cycling in a basic aqueous solution removed the adsorbed ionic species, resulting in electrocatalytic oxidation of ethanol at the AuPd alloy nanoparticle-immobilized HOPG electrode. The electrocatalytic activity of AuPd nanoalloy particles varied upon changing the fraction of Au and Pd in the particles, and alloy particles having an Au fraction of ca. 0.61 exhibited the maximum activity against ethanol oxidation, being higher than the activity of the pure Pt surface. Homogeneously alloyed AuPd particles, prepared by sputter deposition in an ionic liquid, exhibited the high electrocatalytic activity for ethanol oxidation.