One-pot synthesis of Pt/CeO2/C catalyst for enhancing the SO2 electrooxidation

Abstract SO 2 is one of the critical poisoning species to Pt based catalysts of proton exchange membrane fuel cells (PEMFCs). Catalysts suffer severe performance degradation even trace amount of SO 2 presenting in the hydrogen or air. To enhance the SO 2 electrooxidation of Pt catalyst, we prepared Pt/CeO 2 /C composite catalysts via a one-pot synthesis method. The CeO 2 nanoparticles initially deposited on carbon black, and followed by Pt nanoparticles selectively nucleating on CeO 2 surface. The rich Pt-CeO 2 interface facilitates the oxygen migration, enhancing SO 2 electrooxidation and ORR activity. The catalysts containing 10 and 20 wt.% CeO 2 show the best performance, i.e., peak potentials of SO 2 electrooxidation are 0.06 and 0.09 V lower than Pt/C, respectively, ORR mass activity is over twofold greater, and area-specific activity is one fourth higher than Pt/C. Oxygen provided by CeO 2 reduced the SO 2 coverage on Pt surface and changed the dominant adsorbing state of SO 2 , hence, is vital to the SO 2 electrooxidation. Besides, accelerated durability test confirmed that CeO 2 could also improve the durability of Pt based catalysts.