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 mgPt cm–2. This study offers a novel approach for designing phosphate-tolerant electrocatalysts for HT-PEMFCs.