Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
DOI: https://doi.org/10.29363/nanoge.nfm.2022.236
Publication date: 11th July 2022
To further expand fuel cell technology, a full understanding of the processes taking place at the surface of the electrodes is needed. After decades of investigation, platinum (Pt) is still the single metal with the highest electrocatalytic activity for the reactions taking place within a fuel cell. It has been shown that its catalytic properties can be further exploited by tuning the surface structure and composition. Therefore, preparing and understanding bimetallic surfaces is of paramount importance if one is to improve fuel cell performance [1].
Bi-metallic catalysts with well-defined surface structure can be prepared by depositing adatoms on Pt single crystal electrodes [2], through the formation of surface alloys by co-deposition and gently annealing [3], or, as in this study, by preparing bulk alloy single crystal surfaces [4]. Here, the preparation of Pt–Pd bulk alloy single crystal electrodes following a modification of the Clavilier bead method has been revised. The surface composition and structure of the electrodes have been analyzed by X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED), respectively, pointing out that the surfaces prepared by this methodology are well-defined and give rise to surface compositions close to the nominal ones. Subsequent correlation between surface structure and composition and the voltammetric response has been assessed by performing cyclic voltammetry in different supporting electrolytes, displaying a characteristic and reproducible response for each surface.
Reportedly, very few studies have been accomplished for fuel cell reactions on well-defined bulk Pt-Pd alloys. Here, we will also show the electrocatalytic behavior of a collection of Pt-Pd single crystal surfaces for certain reactions of interest, such as formic acid oxidation and oxygen reduction reaction. Therefore, this contribution is a step forward towards the understanding of the combined role of surface structure and composition of Pt-Pd bulk single crystal electrodes in their catalytic behavior.
This research has been funded by the Max Planck Society through the Max Planck Partner Group Program between Fritz-Haber Institute Berlin and the University of Alicante. The financial support from Generalitat Valenciana (CDEIGENT/2019/018) is also acknowledged.