Sulfur Dioxide-Tolerant Core@shell Ru@Pt Catalysts Toward Oxygen Electro-Reduction

Proton exchange membrane fuel cells (PEMFCs) have achieved milestones in performance improvements and commercial launches. In the typical commercialized PEMFCs, the compressed air to cathode is usually supplied from ambient air, assuming that no costly pre-purification system is applied. Therefore, the working PEMFCs may suffer from the negative effects of the air impurities. In this regard, SO2, as the most poisonous species, may be fed along with air at the cathode and strongly adsorbed on the Pt surface, leading to Pt site deactivation. To address this challenge, we published a series of works in terms of poisoning mechanisms, regeneration protocols, and advanced poisoning-tolerant catalysts. Herein, we are aiming at developing a SO2-tolerant electrocatalyst toward a cathodic oxygen reduction reaction (ORR). We reasonably incorporate the Ru, synthesize Ru@Pt core@shell catalysts and investigate the relationships among Ru incorporation, ORR activity and SO2 tolerance. Impressively, the Ru@Pt/C exhibits higher initial ORR activity (0.288 A mg−1Pt), better SO2 poisoning resistance (33% loss in initial activity) than that of commercial Pt/C catalysts (0.252 A mg−1Pt; 62% loss). The engineered affinity between Pt and SO2 in the presence of Ru is uncovered to account for the improvement.