Palladium-ceria nanocatalyst for hydrogen oxidation in alkaline media: Optimization of the Pd-CeO2 interface

The development of Pt-free catalyst for anion exchange membrane fuel cells is limited by the sluggish hydrogen oxidation reaction (HOR) at the anode. Previously, the use of CeO2 as a catalyst promoter facilitated drastic ennoblement of Pd for the HOR kinetics in base media. However, further optimization and understanding of the Pd-CeO2 interaction, surface properties, and their influence on HOR are still needed. In this work, three types of Pd-CeO2/C catalysts are synthesized by a flame-based process, where the Pd-CeO2 interface and the HOR activity are improved as compared to catalysts prepared by wet-chemistry processes. The correlation between the Pd-CeO2 interaction and the HOR activity is established through comparisons of three types of Pd-CeO2/C synthesized catalysts using electrochemical techniques and X-ray photoelectron spectroscopy.