Effects of the PdO nanoflake support on electrocatalytic activity of Pt nanoparticles toward methanol oxidation in acidic solutions

Abstract

We prepared PdO nanoflake thin films on carbon cloths by reactive sputtering deposition, and studied electrocatalytic performance of Pt nanoparticles electrodeposited on the PdO thin film in methanol oxidation reaction (MOR) in acidic media. The PdO nanoflake thin film exhibits a cyclic voltamperometric (CV) behavior similar to metallic Pd electrodes because a metallic Pd surface layer is formed on the PdO thin film electrode under the CV measurement condition. The nanoflake morphology of the PdO electrode provides a large surface area for Pt nanoparticle loading, resulting in a large electrochemical active surface area (ESA). The Pt/PdO electrode has a high electrocatalytic activity toward MOR, and the good electrocatalytic performance of the Pt/PdO electrode is ascribed to a high CO tolerance and the large ESA. We suggest that the high CO tolerance of the catalyst on the Pt/PdO electrode is a result of the synergism of the bifunctional mechanism and the electronic effect. XPS analyses indicate that negative charge transfer occurs from the PdO support to the Pt nanoparticles, indicating the presence of the electronic effect. Pt nanoparticles on the PdO support can greatly alleviate the nanoflake damage during the CV measurement, which results from anodic dissolution of metal Pd from the PdO support in acidic media.