Fine Structure Effect of PdCo electrocatalyst for Oxygen Reduction Reaction Activity: Based on X-ray Absorption Spectroscopy Studies with Synchrotron Beam

Abstract

:In this study, we have demonstrated the fine structure effect of PdCo electrocatalyst on oxygen reduction reaction activity with different alloy composition and heat-treatment time. In order to identify the intrinsic factors for the electrocatalytic activity, various X-ray analyses were used, including inductively coupled plasma-atomic emission spectrometer, transmission electron microscopy, X-ray diffractometer, and X-ray Absorption Spectroscopy technique. In particular, extended X-ray absorption fine structure was employed to extract the structural parameters required for understanding the atomic distribution and alloying extent, and to identify the corresponding simulated structures by using FEFF8 code and IFEFFIT software. The electrocatalytic activity of PdCo alloy nanoparticles for the oxygen reduction reaction was evaluated by using rotating disk electrode technique and correlated to the change in structural parameters. We have found that Pd-rich surface was formed on the Co core with increasing heating time over 5 hours. Such core shell structure of PdCo/C showed that a superior oxygen reduction reaction activity than pure Pd/C or alloy phase of PdCo/C electrocatalysts, because the adsorption energy of adsorbates was apparently reduced by lowering the dband center of the Pd skin due to a combination of the compressive strain effect and ligand effect.

Preparation of Bimetallic Pd-Co Nanoparticles on Graphene Support for Use as Methanol Tolerant Oxygen Reduction Electrocatalysts

“…Several carbon-supported Pd-based bimetallic cathode materials have already been reported [11][12][13][14][15][16]. Graphene is an allotrope of carbon (like diamond, fullerene, carbon nanotubes (CNT) etc.)…”

Preparation, characterization and electrocatalytic activity for oxygen reduction reaction in PEMFCs of bimetallic PdNi nanoalloy

“…Palladium nanoalloys are being currently used to accelerate the kinetics on the cathode electrode obtaining the maximum catalytic activity towards the ORR [18,35]. In the present work, a modified polyol reduction method used to synthesize a nanostructured carbon-supported PdNi catalyst to improve the electrochemical performance of Pd catalysts.…”