Paper on Clarifying Hydrogen Oxidation on Pd/CeOx
18/08/2020 - Recent work is published in Chemistry of Materials
Article title: On the Improved Hydrogen Oxidation Reaction Activity and Stability of Buried Metal-Oxide Electrocatalyst Interfaces
Authors: Florian D Speck, Farhan SM Ali, Michael TY Paul, Ramesh K Singh, Thomas Böhm, André Hofer, Olga Kasian, Simon Thiele, Julien Bachmann, Dario R Dekel, Tanja Kallio, Serhiy Cherevko
The current in anion exchange membrane fuel cells (AEMFC) lies at the anode catalyst side, where the hydrogen oxidation reaction (HOR) occurs. Due to the specific requirements of this reaction in alkaline, only platinum group metals (PGM) presents the required H2 adsorption capability and metallic oxidation state. The Pd/CeOx system offers to tune of the performance of poor Pd catalysts and therefore is treated as an alternative to Pt HOR catalysts. However, the Literature is in disagreement about the mechanism, and therefore an ideal catalyst system is still elusive.
In this work, we simplified the system to a 2D model using physical vapor- and atomic layer deposition techniques. Contrary to some reports we show that CeOx does not influence the oxidation state of Pd, and that the fully CeOx buried Pd surface is more stable and more active than the blank one. We conclude that this is due to selective diffusion through such an overlayer, which additionally provides OH- supply to Pd, which increases the rate of HOR.
For the whole story in Chemistry of Materials, please go to: https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.0c02048