CeO₂-Pt Synergistic Electrocatalysts for Enhanced Phosphoric Acid Tolerance in High-Temperature PEM Fuel Cells

In high-temperature proton exchange membrane fuel cells (HT-PEMFCs), phosphoric acid (PA) facilitates proton conduction. However, phosphate ions can form strong bonds with the Pt surface through Pt-O bonds, leading to the poisoning of the Pt active sites on the catalyst. This ultimately causes catalyst deactivation and slows the oxygen reduction reaction (ORR) kinetics. In this study, we prepared a carbon-cerium oxide (C-CeO₂) composite support through rotary evaporation and calcination. Subsequently, Pt nanoparticles supported on the C-CeO₂ composite were synthesized using the conventional ethylene glycol reduction method, yielding excellent resistance to PA. In the C-CeO₂-Pt catalyst, the synergistic interaction between CeO₂ and Pt effectively alters the electronic structure of Pt, thereby weakening the adsorption energy of phosphate ions on the catalyst surface. Additionally, the introduction of CeO₂ significantly enhances the metal-support interaction and suppresses the agglomeration of Pt particles. This promotes a uniform distribution of nanoparticles and prevents catalyst separation and aggregation during the accelerated durability test (ADT) process. Results from phosphate poisoning tests using room-temperature rotating disk electrode analysis indicate that the C-CeO₂-Pt catalyst exhibits exceptional phosphate tolerance, superior ORR activity, and excellent stability. Under a H₂-O₂ atmosphere, the HT-PEMFCs assembled with C-CeO₂-Pt electrocatalysts achieved a peak power density of 603.78 mW cm^-2 at a low platinum loading of 0.3 mg_Pt cm^-2. This study offers a novel approach for designing phosphate-tolerant electrocatalysts for HT-PEMFCs.